Padding and margin have two different purposes. Padding is for spacing within elements. Margin is for spacing between elements. However, there's more to it!
Margin vs Padding. Margin is an element's personal space —…, by Kunal, Frontend Shortcut
Margin & padding: the creation of negative space, by Julian Poplawski
CSS Margin vs. Padding: What's the Difference?
Padding vs Margin: The Definitive Guide – UX Engineer
Padding vs Margin: The Definitive Guide – UX Engineer
When to use Padding and Margin. Small details really matter., by Sung Park, Sketchware
When to use Padding and Margin. Small details really matter., by Sung Park, Sketchware
Photonics, Free Full-Text
Padding vs Margin Explained - Visual Composer Website Builder