It varies from country to country. Most countries will insist that the denomination of the stamp be marked through in some way, and others have additional restrictions. For US information, see the link below.
Switzerland
what led to the idea of usingpostage stamps
Safest to assume everything is unless it says otherwise.
Franking privilege
Franking Privilege
The Forever stamp is not to be used for postage overseas. If you are mailing a letter to a soldier, and using the APO box, normal rates apply. You would be able to use a Forever stamp for that letter.
Make sure the images you're using are in the public domain or have Creative Commons licenses.
Yes. The H series stamps are only worth 33 cents. You need to add enough postage to total the current rate.
Yes. All international mail is sent with the postage from the country of origin.
For First Class postage, one ounce using the Liberty Bell forever stamp, 44 cents.
Without permission, yes. Even creating a GIF from existing images or video can be infringing.
The first postage stamp in England in 1840 Known as Penny Black, the tiny stamps (3/4 by 7/8 inches) with Queen Victoria's profile were printed using only black ink.