Indents can be adjusted in your theme settings under Print Layout.
Go to the Formatting Tab.
Clicking the three dots next to the theme name and select Edit or Edit as New Theme.
Go to Print Layout.
Click in the Indents box and move the arrows up and down to change the sizing.
For more details on how to set up or adjust your theme settings, you can refer to this tutorial: Create a Custom Theme. It provides detailed instructions and tips on creating and modifying your theme.