Buying blank postcard paper allows you to create custom, professional-looking mailers at home for marketing, invitations, or personal greetings. To ensure your postcards are mailable, the paper must meet specific USPS guidelines, generally requiring a minimum size of 3.5" x 5" and a thickness of at least 0.007 inches. Types of Blank Postcard Paper
: Heavyweight stock (around 140 lb) designed for hand-painting or artistic media. Printing Your Own Postcards: A Complete Guide - Ftp
: Thick, brown paper (often 350 GSM) suitable for a rustic look.