It is a one-click preset that instantly removes the background from an image using Photoshop's Subject Select and background deletion capabilities.
It is located in the Quick Actions panel in Photoshop. Click the + icon in the Quick Actions panel and search for "Remove Background".
It uses Subject Select to automatically detect and select the main foreground subject, creates a layer mask, then deletes the leftover background layer.
Photoshop Remove Background works best on images with high contrast between subject and background. Portraits, products, and still objects tend to produce good results.
Remove Background is much faster and automatic versus manually erasing the background with the Eraser tool. But the manual eraser allows more custom control if needed.
The Remove Background tool creates both a selection around the subject and a layer mask to isolate it from the background