Online earning through blogging was one of the best means a decade ago. Now blogging still earns but only through niche blogs that have quality and are helpful to a segment of people in general.
Website and blogging both are different things but is generally considered as one thing. To give you an idea to differentiate between a blog and website you can see a technical machine that comes with a detailed manual. Here the machine is the website and manual being the blog. A website can have a blog that gives some more information or details about the product/service/field it deals in.
Generally a website is an official account and a mean of interface between a business and people while a blog can be an informal mean of communication and dissemination off information.
Coming to earning from blogging, this is now a tricky thing. Many blogs make alot of money while most struggle to find an audience. Google also is updating itself and steadily degrading blogs that do not add value to the user or are not regularly updated. Gone are the days when you write a few posts and make a the cash bell ringing.
If we simply follow the Google policy of value addition through information then earning from blogging is possible and the income slowly grows, but one must understand that it takes time and effort.
One can earn from Google Adsense or other alternative advertising platforms like Medianet, Infolinks, Adsterra, etc. and as the blog grows one can add affiliates, or sell products directly (if it being a niche blog), or sell space for advertisement, or earn by paid backlinks, or charge the user itself for the specific services or advices provided on your blog.
All the above means of earning are a seprate topic altogether and each have a detailed methodology which you will have to learn before you jump into it.
But, the first thin is that you must have a skill or niche which will allow you to work upon passionately. If you are going to start a blog with no clear goal and topic, then it is advised not to do so, as that will lead to only loss of time and energy and an addition of another blog to already billions of sites and blogs.
More than 90% of the sites and blogs are dormant with Nil or very low traffic, don't become a part of that.
Regarding promotion of your blog, digital marketing will cover all the things like SEO, SMO, paid promotions and this again is a specific field which you must update yourself with to get noticed and attract users to your blog.
You will have to provide quality original content with value addition to a specific segment and make your self noticed in the crowd and at the same time stay relevant. Blogging is not a get rich quick formula but a full time profession as of now and is getting more fiercely competitive and organised.
Live before you leave.