Can I register MSME without GST and make money

Hi all, 

I would like to know if I can sell a product first  make some money and register company later and show all money under company as company Income tax is net profits and personal Income tax is on whole income.

And 

second query is: Can I register MSME certificate, with normal savings bank account or personal current account, and no other registration and say that Income I make is from Business, and later register a GST and all that?