Formal:
* Pouvez-vous m'apprendre le français? (This is the most polite and formal way to ask.)
Informal:
* Tu peux me apprendre le français? (This is more casual and is used with friends or family.)
* Peux-tu me apprendre le français? (This is also informal, but slightly more polite than "Tu peux...")
Even more casual:
* Tu veux bien me apprendre le français? (This is very informal and implies that you are asking someone to do you a favor.)
Other options:
* J'aimerais apprendre le français. Pourriez-vous m'aider? (This means "I would like to learn French. Could you help me?")
* Je voudrais apprendre le français. Pourriez-vous me donner des cours? (This means "I would like to learn French. Could you give me lessons?")
The best way to say it will depend on the context and your relationship with the person you are asking.