Adding Buttons to Toolbars
From LibreOffice Help
Open the context menu of the toolbar (right click) and choose Visible Buttons and then select the button you want to display.
- Choose Tools - Customize, and click on the Toolbars tab.
- In the Toolbars box, select the toolbar you want to change.
- Click Add Commands , select the new command, then click Add.
- If you want, you can rearrange the Commands list by selecting a command name and clicking Move Up and Move Down.
- Click OK.