It’s no longer installed in the default installation. And, you probably shouldn’t use it. Apache mod_dav is not suitable for a modern shared hosting environment, from a security perspective.
If your system is not a shared system (i.e. only trusted users will have access), you can install the wbm-virtualmin-dav module, and make sure the Apache dav module is installed and enabled. But, this module is deprecated and no longer receives updates or support. There are probably better ways to provide access to files to your users (including the File Manager in Usermin/Webmin).
I installed the module wbm-virtualmin-dav but I miss a lot of parts after activated it, in the new Virtualmin GPL edition.
No able to find these parts:
Next enable DAV login for your domain / user under Virtualmin -> Edit Users -> Other User Permissions
Under Virtualmin -> Services -> Dav Authentication, set Auth type to ‘Basic’ and DAV username mode to ‘POP3/FTP’ (these are the defaults)
Go to Virtualmin -> Services -> Configure Website and click on ‘Location /dav’ under Per-Directory options then choose ‘Access Control’. Click on ‘Edit Users’ (next to ‘User text file’) then click on the user you wish to set the DAV password for. Now, click on the ‘Plain text’ option and enter your password before clicking ‘Save’.```