When I began EME operation, I decided to confirm QSOs with a QSL-card related to Moonbounce. I had a picture of my EME-antennas pointing at the Moon. The picture was taken at dawn, and both the 4 antennas and the Moon were clearly visible.
There are many websites, where print-shop owners offer QSL printing service. I selected UX5UO
due to his fair pricing and great design flexibility.