Open HMK File
The HMK format and extension file is used as a greeting card project created with Hallmark Card Studio.
Hallmark Card Studio is a software created by Hallmark Cards Inc. which is a private, family-owned American company based in Kansas City, Missouri.
Therefore, the HMK file can be a birthday card, an invitation, a letter, or another type of card.
The HMK can include images (user photos or images included in the program) and custom formatted text.
For a professional look, cards created in the HMK format can be printed on Hallmark Premium Blank Greeting Cards, a heavyweight 85lb card stock with a coated matte finish.