To add a margin of 5 pixels to all buttons used in your Avada Theme:

1. Log into WordPress.
2. Click on 'Appearance'.
3. Click on 'Theme Options'.
4. Click on the 'Custom CSS' tab.
5. In the text field enter the CSS.fusion-button{margin: 5px 5px 5px 5px;}
6. Click the 'Save All Changes' button.