Since you are buying a company it goes by the COMPANIES ACT 1956 provisions. The transfer of ownership(share holding ) of the company takes place, you (as transferee) the company (as transferrer). You can buy or purchase the assets and liabilities or as your mutual dealing only assets or only liabilities or partly assets partly liabilities.
You can buy the company as :
1)in your individual capacity(proprietary firm).
You have to comply lots of formalities specified under the acts informing registrar of companies, passing out resolutions etc( if you are as a company) 3rd December 2010 From India