You can specify a few different padding options inside the Drag & Drop email editor, and they can be a bit tricky to understand.
- Global Style Padding - padding is always removed on mobile viewports (meaning people who look at your email on their phones, mostly)
- Section Padding - option to remove padding on mobile can be set. Default is "no"
You can see the red below indicates global padding, where the white is padding controlled for a single section: