Same just like adding images to description.
.
You can find some gifs from Tenor or any kind of it.

@griges no problem

@MartennLockkenn thank you!

@griges postimages.com enter and copy the section that says direct link

@MartennLockkenn so, same like images, but just gif file?
can you recommend me one, preferably free

youtube?? it can be video?