Just paste in a url: https://giphy.com/gifs/animation-ryan-seslow-ryanseslow-4HmjNLWlzis3H4V0Il on a line by itself.

https://giphy.com/gifs/animation-ryan-seslow-ryanseslow-4HmjNLWlzis3H4V0Il

Giphy may be blocked on school networks.

Block Editor

The gif block which requires Jetpack to be turned on, allows you to search for a gif or paste in a url.