There are several ways you can create a simple loan contract. It makes no difference on which side of the deal are you, the document should be the same. The simplest, of course, would be initial and sign a piece of paper on which you have jotted down the terms of the agreement. That would be legal, but no matter how simple the agreement may be, it should be put in clear, concise straightforward language.
There are several places to find help in producing the document. What you want is ordinary language stating that you are the lender or the borrower. The document should define the terms of the loan. This includes the amount of the loan, the interest rate used and the time allowed to repay. In a more complex transaction, you might address paying the loan back before the due date and if doing so would be penalized.
If you need a quick note prepared, Rocketlawyer has a boiler plate loan agreement you can customize. This web site has a number of simple contracts you can adapt for almost any uncomplicated legal matter. The simple contract can be done for free, but you have to join the Rocketlawyer legal service. If you cancel the membership before a week, there is no cost.
LawDepot has a more comprehensive list of documents from which to choose. The site has the user to fill in the information from which it produces the simple contract. You then print out the complete document. There is a change for this.
LoanBack also offers do it yourself legal forms. At this site, you outline the terms and conditions of the simple contract . From it, it produces the document for you. The site charges a fee for this.
You do not need to get into a business transaction involving money and simple contract with getting help. There are several places on the internet that can assist you.