Are there any envelope postal restictions? Can I draw on them or put stickers on them?

I want to send a letter to my friend in England. I want to make the envelope attractive. Is there any regulations or restrictions about this?Are there any envelope postal restictions? Can I draw on them or put stickers on them?
I have mailed various items: record album sleeves, addressed..... a plastic fish..... a pie pan with address label on the bottom to my Amish friends who gave me a pie, and mailing was cheaper than driving to return it.... an addressed soda bottle, plastic, with decorations %26amp; note enclosed.



I draw on envelopes, front and back, and if address is clear, there will be no problem.



The postal workers sometimes roll their eyes, but as long as I am paying postage the mail does go through.
i advice you to buy a decorative envelope and better make your design on the letter and also put your stickers like that re your friend can keep it more sure,as the envelope most people destroy it when they open the letters.Are there any envelope postal restictions? Can I draw on them or put stickers on them?
Aslong as you do not draw over the stamps or the adresses, then its ok.



I have sent a letter art letter to Nintendo Power once. Didn't get returned to sender, so I assume it made it.
Not that I know of, I do it all the time. Ensure it is not inappropriate and doesn't take away from the addresses, if you can do the major stuff on the back.Are there any envelope postal restictions? Can I draw on them or put stickers on them?
i dont think so, as long as the address is clear.