Hi! (or "Bonjour")

I want to ask you how i cant do that efect:

http://wfwp.forumactif.com/adoptons-un-pokemon-f233/bottin-quel-pokemon-a-ete-attrape-t86.htm

When you pass the mouse by the names appear a rectangle with information

I saw this efect, but always is using images... never using text

There are "Infobulle". (
You will find that you want in this topic :

https://css-actif.forumactif.org/intermediaire-f15/faire-une-infobulle-t103.htm

Thanks