What are things to do create new company for web designing & development as sole proprietor?

I am from Tamilnadu, I have to plan open a new company and owned by me. That company based on Web Design & Development, Software Development.

Kindly assist me as following queries:

• What are things I have to do company open process under GST/VAT?
• What are Taxes I have to pay?
• What are thinks I have to show in my Invoices?
• Is any return submit by monthly?