We use to deploy office addin manifest file by windows shared folder, due to some network problem, now it need be done by sharepoint. but there is no office addin options after move the manifest file to sharepoint server. I'm using the template manifest file on microsoft docs(https://docs.microsoft.com/en-us/office/dev/add-ins/develop/add-in-manifests?tabs=tabid-1)
(1)manifest file on sharepoint server and the links
(2)office trust center setting(all good with shared files, have problem with sharepoint deployment)
(3)office insert ribbon