Is there any learn tools for opening and free ?

You can prefer to lichess.org/video?tags=opening for openings , which are free for everyone!

Lichess' opening explorer is an excellent way to build your opening repertoire. If you feel like you need more explanation, you can find videos about openings on YouTube and/or Short & Sweet (Free) courses on Chessable.

#4 The original poster wants the content to be free to use.

maybe openingtree.com/?

You could try chessable