Remove the background of a picture in Office - Microsoft Support
https://support.microsoft.com/en-us/office/remove-the-background-of-a-picture-in-office-c0819a62-6844-4190-8d67-6fb1713a12bf
On the toolbar, select Picture Format > Remove Background, or Format > Remove Background. If you don't see Remove Background, make sure you have selected a picture. You might have to double-click the picture to select it and open the Picture Format tab. The default background area will be colored magenta to mark it for removal, while the ...