As the details of the terms and conditions of your job are not detailed, I shall give my suggestions and opinion totally based on the narration in the question.
Overall, I feel that your company has followed what is followed in many other establishments. A company decides about compensating its employees depending on its profit, surplus funds, turnover, demand for its products and services etc. In some long established and large organisations there may be approved trade unions and there may be some mutually accepted settlements But smaller organisations may no be able to follow those system.
In the present case, the company is" saying pay for travel charges from your own pocket first. They will reimburse the amount later when we will join the office. "- That is there in most organisations. That is called re-reimbursement of actual expenses. Every company does that but some may give some amount as advance, t be adjusted when the actual expense claim is submitted.
"whether a company can forcibly transfer a employ without his consent."-- Any job will have a condition expressed or implied that employee is subject to transfer . Hence yo cannot say it is a forced transfer. Company is telling you to resign if you do not want a transfer. They may have a real compelling justification for that.
"Our company main intension behind this is that all company employees leave their job with one month salary."- it may be just your presumption or may be true also. The company may be facing business reduction or finance problem and they may be resorting to some cost cut.
"Please suggest the legal option for us"- I cannot give a legal option as I do not know what were the job contract terms. You can claim compensation only as per the job contract terms. The company is not making a lockout, not terminating employees, but only transferring its employee to anew work spot. That is just natural and normal..
However what you can try is to ask for some advance for transfer travelling expenses, in case you are facing financial problems. The company may accept it on human considerations or simply reject it as they have clearly said to spend first and then get reimburse.
It is for you to decide by evaluating your priorities and problems. You have to asses and ensure about alternative job possibility in case you think of resigning. It should not be a case of falling from the frying pan to the burning fire.