How can I reset my MacBook Air without knowing the password or Apple ID?

The MacBook is activation locked, and because of the reason of activation lock, it is a theft deterrent system, this is not easily fixable.

If you have valid proof of purchase information you can start an Activation Lock support request.

A fix for what? You've encountered activation lock. It's an anti-theft mechanism designed to make it unusable to anyone other than the rightful owner.

Without the credentials for the account used to lock it or the original proof of purchase, the lock can't be removed.

Here is something you can try:

You would have to erase the MacBook for this.

• Turn off the MacBook
• Power it back on, and immediately hold Command + R until the Apple logo shows up.
• From the top left menu bar, click Recovery Assistant > Erase Mac.
• Follow the steps

hope this helps!!

Unfortunately, that means it is a boat anchor.

Recycle it.

Try resetting the password. Seeing that the Apple ID is know, then you can go to https://iforgot.apple.com/ .

No.