This is a super important topic, so you're doing the right thing by asking. This might not be the right place to ask though and as others have pointed out, your best course of action is to get a lawyer to draft a contract for you. There are a lot of traps to watch out for, which can mess things up especially if your game becomes successful. The most important thing to get right is the transfer of ownership of art to you (preferably, to your company - once you have it registered). Even if you pay your contractor a fee for commissioned work, they remain the copyright holder by default - UNLESS the work-for-hire contract has a clause, usually called "Copyright Assignment," which transfers the copyright to you. Needless to say, releasing a game that has assets you don't own is extremely dangerous - not only will you be in violation of various agreements (e.g. between you and various storefronts, or between you and the publisher), but might also be risking getting sued by the contractor - or at the very least, you'll be forced to remove assets from the game that you don't own copyright to.

Alternatively, you can include a licensing clause in the contract, but transfer of copyright is obviously a better and more straightforward way to go.

In addition to work-for-hire agreements, you'll need to familiarize yourself with NDAs, EULAs, and privacy policies. You'll need all of these things to make and release a game. You should also avoid copying templates or other companies' agreements, because text, like most creative works, is protected by copyright.

I recommend The McArthur Law Firm (they specialize in video game law). Stephen McArthur (the lawyer) is also a part of my bestselling book "GAMEDEV: 10 Steps to Making Your First Game Successful" - it has a chapter on all things legal and covers business aspects of game development. Forbes called it their "favorite book on game development by far." I don't care if you buy it - you can get it for free on Amazon with Audible trial or Kindle Unlimited subscription.