Especially FAQ #12 BG layer is created when saving PSD

If you save the PSD with the background color specified, the specified background color will be automatically created as a “BG layer”.

If you don’t want to create a BG layer, set the background color to “Transparent”.

See below for how to make the background color transparent.

PC

Check “Transparent Background” from the “View” menu.

iPad

① From the command bar menu, tap “Background color”.

② Turn on “Make Transparent”.

iPhone

① Open the paint screen of the work you want to change, and tap “Background Color” from the command bar menu.

② Turn on “Make Transparent”.

Android

① Open the paint screen of the work you want to change, tap the “Edit menu” on the command bar,Tap “Canvas Settings”.

② The canvas setting window will be displayed. Tap the canvas background color.

③ Turn on “Clear”.

▼Related words
I want to delete the BG layer