You can find the endorsement area on the upper side of the check once you flip it over. This area usually includes three to five gray lines where you can provide your signature and write a restrictive endorsement.Under the gray lines, you’ll see a solid black line with instructions telling you not to write in the section below. Ensure your endorsement doesn’t extend beyond that line since the bank needs the space beneath it to process the check. Use a pen instead of a pencil to sign the check so your endorsement can’t be erased.