I am working on an Excel add-in that automates certain specific tasks for my team. I have already created the add-in with Office.js and I have the manifest.xml and the html, css and js files. Is there any way to distribute this add-in internally, without sharing it publicly on the Office store? Are there any limitations or special considerations when installing add-ins privately?

I have tried to manually load the manifest.xml file in Excel. Despite verifying the file format and trying different locations, the add-in does not appear in the list.