If you also want to use the app for Microsoft Outlook in the web browser (OWA), for example, you must set up a connection for the add-in in d.ecs http gateway. You can then distribute the add-in to your users with Microsoft Exchange Admin Center.
This is how it works
Open the d.ecs http gateway configuration screen and select Configuration.
In the Additional Headers area, remove the header rows Content-Security-Policy and X-Frame-Options.
Click Add header to add a new header row.
As the name of the header row, enter Content-Security-Policy.
As the value for the header row, enter frame-ancestorys 'self' <domain name>.office365.com;, if you are using Microsoft Office 365. If you are using Microsoft Exchange On-Premises, enter frame-ancestorys 'self' <domain name>; as the value.
In the header row X-Frame-Options, add the value ALLOW-FROM with <Microsoft Exchange Server URL>.
Save your changes and restart d.ecs http gateway.
Go to Microsoft Exchange Admin Center to distribute the add-in.
Go to Organization > Add-ins and enter the supplied manifest file. You can find the manifest file under: <installation path>\groupware\bin\wwwroot\outlookaddin\manifest\OutlookAddin.xml.
An overview of the supported Outlook client versions can be found here.
After you distribute the add-in, your users can use d.velop documents in Outlook in their web browsers.