Changing the background color can really help make the product or person in your photo pop. It's best practice to select a color that goes well with the color palette of your product.
To change the background color, do the following:
Tap on the background itself or on the background icon 🏞
Tap the first button Replace
Tap the Color tab
Select the color and texture of your choice
To help a bit more with harmonizing the foreground and background, try adding a diffused shadow. Here's how to do this:
Tap the Subject
Tap Shadows
Select a high value for shadow Width
Tap Move 2D and Move 3D to adjust the position
Here is a demo video: