How much do I have to pay even tho I have applecare+ for my mac

You have posted to the 12" Retina MacBook forum area. They were discontinued over 3 years ago, so there is now way that they would still be under Apple Care.

It's important that, among other things, that you actually identify the exact model of your Mac.

See: Writing an effective Apple Support Commun… - Apple Community

In U.S. dollars, any accidental damage (assuming it is repairable at all). Adjust for your locale:

Then you should have posted to the MacBook Air forum area instead of this one.

Plus you should contact Apple directly, as mentioned by "my ginger" and "ku4hx," not something you're doing in this forum.

For some repairs it could be 100% free since you are insured. But if there are major issues expect to pay from your pocket. Another concern is that some repairs aren't covered by AppleCare. All in all, check on the coverage and make sure what you need repaired is covered by Apple. Hope this helps!

We do not work for Apple. Only Apple can tell you that. Make an appointment.Contact - Official Apple Support

Good information here: https://appleinsider.com/inside/applecare. But you should always contact Apple to get the very latest figures.

Different areas of the world may have different pricing policies. Asking other users is not helpful to you. You need to contact Apple for a current price.