Miscellaneous topics that do not fit into specific categories.
In the desktop version of Word for Windows and MacOS, you can assign a custom keyboard shortcut to almost any action. In Word for Windows: File > Options > Customize Ribbon > Customize... (next to Keyboard shortcuts):
Select a category, then select a command.
Click in the 'Press new shortcut key' box and press the desired shortcut.
Click Assign.
In the desktop version of Excel, you can only assign keyboard shortcuts to macros.
PowerPoint and Outlook don't have the option to create custom keyboard shortcuts, as far as I know.