: Stamps was a companion application for the iPhone that worked alongside the Direct Mail email marketing software on macOS.

If your goal is more functional, such as stamping "Approved" or "Reviewed" on a document, several Mac-native tools offer this:

: This app was primarily active during the iOS 7 era (circa 2013) and was a major milestone for the Direct Mail team as their first mobile application. 2. Using Digital Stamps in macOS Pages