Editing photos on my MacBook Air

You could try this

Extract an image or remove a background in Preview on MacOfficial Apple Support › guide › preview › mac

It is not really comfortable, but it may work.

If you need more you will need an additional App, I use Photoshop but that makes only sense if you use it very frequently.

On the current system version you can only remove the background from Portrait Mode photos.

Are you in a hurry? If you wait for the macOS 13 Ventura release in the autumn, you will be able to do this directly in Photos. Photos 8 will allow you to copy the main subject from a photo with a transparent background. It will be supported as a part if the "Visual Lookup" feature. The main subject of a photo can be copied to the clipboard with a transparent background, so you can paste it onto a different background. see: macOS Ventura Preview - New Features - Apple

Lift subject from background

Lift the subject from an image or isolate the subject by removing the background. This works in Photos, Screenshot, Quick Look, Safari, and more.

For the time being, I am using Luminar Neo to separate people from the background.