Verified answer

That's allowed its just like a letter, when I send letters to my grandparents I write them one each but put them in one envelope. Postcards are the same, plus the don't open it to see what's inside. But you can only put one address on it so they will all go to the same place.

you can send them in an envelope if they are all to the same address if not you will need envelope for each one.

It's fine to do that.

Dan.