Using Win10Pro V 1903 with Libre Office V6.2.7.1 which is new to me; I have gone thru most menus and set up page layout etc but cannot seem to find how to add a quick access bar or right click menu for my most frequent features.
Here you will find the documentation of LibreOffice and Writer.
In the Writer manual, page 28, you will find “Customizing toolbars”.
I hope it helps you.
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With me Windows 10 Home; Version 1903; 64-Bit | LibreOffice, Version: 6.3.2.2 (x64).