Not received any formal offer letter from a top MNC

I suggest you, you can trust the HR but the time being you can search for a job in other company too. It is normal in MNC or few top companies in India, or abroad that they take bunch of candidates' interview and just collect the short-listed applications for their long-term requirement.

They call for when they needed only. However, a candidate can't wait for a long duration just to get their uncertain call for from them that may even take almost a six months or a year.

1. Sitting idle without doing anything is not correct.
2. You will get the appointment from that MNC company but it may take another six months also.
3. Instead of simply waiting for that job, attend for interviews in some other companies and if you got selected you can join without giving any assurance for a minimum service period.
4. You can try in other big MNCs also and if you are getting good employment from there you can get into it.
5. Keep trying for other posts and don't waste the time. Nobody will give you a salary for the time lapsed.
6. You can also do some additional certification courses or diploma courses in part-time mode and or distant mode so that they will be useful to you in your future career.
7. These days the colleges are having an understanding with some companies and they select some people from their college and may make the candidates wait for a long time and sometime they may not give offer even after one year also. So keep trying for an alternative.

In my opinion, you have to try some other job also. As you already selected in this MNC company, you must have enquired about the job atmosphere and the salary you will be getting etc. in that company. In this case, you try some other job and if you get a better job offer with a high salary or position, you can decide whether to joining the initial company or not.
Job searching is a procedure where you can meet and speak many highly skilled and highly educated and senior people. You can keep their contact even if you are not joining there. These contacts may help you in future some occasions.
So please go ahead with some good job search and interviews which will give you more experience.

Though the response you are getting from the personnel department of employer where you attended your last interview is positive and you have been apprised of their system of sending of offer - letter in a phase - wised manner, you may trust them. Some MNC companies shortlist the candidates more than the required numbers to take care of any shortfall if some candidates drop the idea of joining.
Though you have been promised to get a call of joining and for which there is no indication of date of joining, you may look out for another job fitting your qualification and experience. Take a feed back of such an organisation. If you are selected in the interview and get a call to join there, you must join the same.
In the meanwhile, you get an appointment of the first organisation, you may over there after tendering your resignation in the new assignment and intimate the previous organisation of your probable date of joining.

Many times in campus recruitment the MNCs are making a list of prospective students for selection to the positions in their organisation but at the same time they only cover some top people and others have to wait indefinitely. There have been many instances like this in the past and even the reputed companies are doing this delay and lingering in issuing the appointment letter. So there is no point in just waiting for them for a call as everytime you enquire they will say that they are on the job and will be issuing the orders soon.

Depending on your interest and attitude you seriously start searching for other opportunities in job portals and upload your CV there so that you can get a feed back for prospective employment from them and can apply for the same.

Meanwhile, you can enhance your skills in your core area by joining some short time course or you can even join a small job near your place. Keeping oneself occupied is very essential at this juncture as even a small remuneration and experience gained can make a change in our status and will bring positivity in our thoughts. Do not feel shy of a small job. Many great people on Earth had very humble beginning before they became legend in their own fields.

These days when industries are doing well so I would advise you not to wait for them to call you. I have heard that many of the companies have cancelled the appointments and selection of new employees to their company.

In my opinion, they may not be having a vacant post, they may have selected you for a new project and they may have not started it due to the poor economy so they may be saying you to wait. It is better that you search for a job instead of sitting idle at home because you don't know when they will call you.

As you are already selected for a job, but employer is telling for wait. Still there is no harm in searching a new job. Infact you should search as country's economy is on crisis and this company might not call every candidate selected in campus placement. So don't waste time and apply and attend interviews. You definitely will get a good job. If you will receive call from this company, you can decide later.

This usually happens in campus recruitments because the companies have to take students as per their signed terms with the particular college or university irrespective of the vacancy they have.
Many times, they hire candidates for different sections (different from their actual specialization) and provide them the required training to work.
So, you may trust the HR and be in touch with him on a regular basis. You may ask him to drop you an email with the status of your offer letter or exact joining date.
You may also contact the placement cell of your institute regarding this as they can also initiate communication with the concerned people of that company.

Apart from this, if you are in need of a job on an urgent basis, keep trying on your own as there are jobs available for freshers in all sectors.

Since your a fresher, its better that you keep trying in other companies as you have not got any formal confirmation from the employer. You can recheck from the HR if they are interested to make you a part of their organization and if the HR says that he/she is willing to make you part of the organization , then you can request them for a Formal Confirmation /Offer Letter with exact date of joining. In case you are not finding a good response, you can just stop thinking about it anymore and look for other avenues.

In some cases , the recruiters just promise to offer job since they are the people who would be helping the Training and Development Trainers/Personality Development Trainers who would promise the students ensuring to make them fit for getting job and they also promise about the Campus recruitment in some numbers to the College management and Students for the particular academic year. This is basically done to get business for their Personality Development courses which they are offering by showing the additional benefit of ensuring campus recruitment. Some may be just a case where they confirm the job just to show that so many number of recruitment have taken place due to the influence of the Personality Development Professionals and this indirectly helps them to get a chance of business for next academic year.

Please stop hoping for it and work on looking for other opportunities. Post your resume in Job Portals like Naukri,Indeed,Shine,etc and also you can keep looking in newspapers for any vacancy details in the relevant filed of your interest

An offer letter is very important thing while you join your company,In the offer letter, it is clearly mentioned about any terms and conditions if the company has. An offer letter is basically a contract letter between the company and you, where compensation package and other working terms and conditions are clearly mentioned.

Every company issues and should issued an offer letter if they are hiring anyone legally. From a legal point of view, offer letter is a very important thing, because of it the proof that the employer is hiring you. Without an offer letter, if you work and they will not pay you to have any proof that you were working for that organization besides other legal implications are also there.

If the company not issued any hard copy of the offer letter for the time being you can ask the HR to sent an email confirmation of your joining otherwise there will be no proof that you have joined. Without any email or hardcopy confirmation it is not wise to join any company. Verbal acknowledgment of joining doesn't make sense.