This is not called a contract, it is called an IOU or IOU. It does not need to be as lengthy as a contract. It only needs to state the borrowing time, borrower, lender, interest, and repayment date. If necessary, also Penalties may be added. The version below is for your reference.

IOU

On ______(date), I, _______(your name) borrow_______(payment amount, please add currency symbol, such as RMB, EUR or GBP) from _______( The name of the lender) with an interest rate of ____________ (specify the interest, if any), and promise to repay the principle and interest within _________ days (the number of days to repay the principal and interest, it can also be changed to the date of completion: on___________).

Date: (date)

Borrower: (signature and seal)

Lender: (signature and seal)