Background removal

The best way is by masking.   Easy way do not work on image that have hard to remove backgrounds.  The easiest way is the remove background button.

Here's a tutorial that uses Select Subject and Layer Masks to remove the background:

Replace a dull background with a fresh new look

Another way that might be even simpler would be to do the following:

1. Select the layer containing the background you want to remove
2. Open the Properties panel (Window > Properties)
3. In the Quick Actions section of the Properties panel, click Remove Background