Business structure affects your tax liability, how you raise money, the paperwork required to file and your personal liability. Choose carefully. Though you may be able to change your structure in the future, it may come with some restrictions.
A quick 5 step process:
Determine the number of owners.
Evaluate tax benefits and drawbacks.
Evaluate liability issues.
Determine the record keeping requirements.
Seek professional advice. Talk with a business attorney or accountant before making your final determination.
The Small Business Administration offers free a business guide to help you through the process.
https://www.sba.gov/business-guide/launch-your-business/choose-business-structure