Members of Professional Photographers of America(PPA) have access to a wealth of resources such as model releases, contracts, and independent agreements at https://www.ppa.com/edu/content.cfm?ItemNumber=1472. Just log in with your member info and the resources will load for you.
Once you have your contract and model release, you can send them via your favorite client management software, DocuSign, Agree, Adobe EchoSign, Mach Forms, or CudaSign.
Mobile Apps- Easy Model Release
It’s also important to note that I would be leery of using someone else’s contract, ones from Pinterest, and random sites on Google. This is one of those time where you need to invest and seek the professional advice of an attorney.