If you want the OneNote web add-ins, you may refer to following reference table of contents:
If you want the OneNote desktop app add-ins, there will be COM add-ins or VBA macros. For more, please refer to my reply in following thread:
As you need further help on programming, I added the tag "Office Development". To help you better, I alos suggest you post a new thread on other forums of OneNote add-ins developer community.
Thanks for your understanding.
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