How to make postcards simply?

1. Select the photos that need to be made into postcards, print them out and stick them on the front of the cardboard, and put stamps on the back, and write down the address, zip code, greeting, etc.

2. Create a blank picture with the size of A3, and typeset the picture according to the size of A3. The pixels of photos and layers are all 300dpi, leaving blood lines. Select the paper to print, and then cut.