What country are you in?
Is your business a sole proprietorship, a LLC, or a sub-chapter S corporation?
Will you be keeping the business financial records or have you hired an accountant to do that for you?
Which accounting method will you be using - the accrual accounting method or the cash accounting method?
Which insurance company(s) are you using for your business liability insurance, for errors and omission (E&O) insurance, and for equipment insurance?
Copyright release is not a good term to use, from a legal perspective.
At the end of the day, the copyrights to the photos you make are a valuable asset you own and copyright is a bundle of rights.
You can rent those rights in a piecemeal manner.
Also copyright is federal law here in the USA, so it's the same in all 50 states and for each business -
www.copyright.gov
Instead use the term - use license. In retail photography a use license is often called a print release.
A use license/print release is a type of photograph rental agreement.
Unless you enjoy taking on the risk of spending time and money on lawyers and court costs, yes - you need a well written contract that every customer signs, and valid model releases on file. Also note that there are other details regarding model and property releases you need to know about:
A Digital Photographer's Guide to Model Releases: Making the Best Business Decisions with Your Photos of People, Places and Things
Having a qualifies attorney review or write all your legal documents is highly recommended.
Model release law varies by state in the USA so using a generic one you find online might backfire on you.
FWIW - minors do not have sufficient legal standing to sign contracts nor model releases - their parents have to sign for them.
Starting & Managing a Business | SBA.gov
Contact your city government to discover what their requirements are for starting/registering a business.
Contact your state government to discover what the state requirements are for starting/registering a business.