The person preparing a check positions the check in the checkwriter so its print-heads are centered over the field on the check where the amount of the check would otherwise be written out in words. Using a series of levers or buttons on the checkwriter's control panel, the operator enters the monetary amount of the check. This amount is then printed onto the check by the operator pulling a lever on the side of the unit (or by pressing a button on electric units). This brings the print-heads down upon a wide inked (usually multicolor) ribbon through which they print the selected amount on the check, with a prefix and suffix to prevent a fraudster from adding extra digits. Entering $6,762.64, for example, will produce text reading "TheSum6762dol's64cts".
There is a series of (usually) horizontal indentations on a pressure bar brought up underneath the check during this process, which matches similar indentations on the print-heads. This embosses the numeric amount through the paper of the check form, strongly discouraging any attempt to alter or raise this amount.
Any person, business, or organization which regularly prepares remittances by issuing high-amount checks would (or should) use a checkwriter. Financial institutions regularly use them to prepare cashier's checks, and they are also used by issuers of money orders such as the United States Postal Service.