Can I do monthly installments on a Mac book air with my Apple Card even if I was only approved for 250?

Your credit limit needs to cover the entirety of the cost of the Mac, if it does not, then you will only be able to finance the amount it does cover, and the rest will need to be paid in one payment during purchase.

what if ur credit is not very good

Mikim21 wrote:

what if ur credit is not very good

Then you need to find other ways to finance it that is not the Apple Card and try to improve your credit in the meantime.