OneNote includes 29 category tags to organize and find your notes, under the Home tab. Click on the second dropdown arrow to scroll through and show them all:
At the bottom of that dropdown, choose "Customize Tags".
To delete a tag, select it with the mouse (or Up/Down keys) and click on the "x" remove button:
To change a tag's icon / label / color, select it and click "Modify Tag" (bottom). • Type a new label in the Display name field, to appear in the tag-search tool and the Home tab listing.
• Optionally pick another symbol from the first dropdown - pick the first icon (double-A / none) to remove the image: this is useful for "extra" categories you assign (avoids showing too many icons on the left). You can't use custom icons.
• You can pick one of 40 font colors: the "Automatic" default follows your theme (generally black).
• You can also pick one of 15 background colors for a highlight effect; the default of "None" means transparent.
Click OK to save the changes, or Cancel to keep the current settings.
To create your own tag, click on the "New Tag" button at the bottom (same process as above).
To assign a (different) keyboard shortcut to a tag, just move it up or down in the listing, using the up and down arrow buttons: the first one automatically gets the "Ctrl+1" hotkey, and sequentially thereafter until you reach "Ctrl+9". (Note:Ctrl+0 (zero) is a dedicated keystroke to remove tags.)