OfficeJS Add-In Overview:
https://learn.microsoft.com/en-us/office/dev/add-ins/overview/office-add-ins
OfficeJS Add-In Requirement Sets:
https://learn.microsoft.com/en-us/office/dev/add-ins/develop/office-versions-and-requirement-sets
OfficeJS Add-In Testing/Debugging Information (For Developers):
https://learn.microsoft.com/en-us/office/dev/add-ins/testing/test-debug-office-add-ins
https://learn.microsoft.com/en-us/office/dev/add-ins/testing/debug-add-ins-overview
OfficeJS Add-In Publishing Information:
https://learn.microsoft.com/en-us/office/dev/add-ins/publish/publish