Open a command prompt using Run as Administrator.
Since this is an IIS backup, it will backup all IIS websites.
Add Backup:
%windir%\system32\inetsrv\appcmd.exe add backup "Backup1"
If you omit the backup name, one will be generated based on the current date and time.
E.g.
%windir%\system32\inetsrv\appcmd.exe add backup BACKUP object "20180204T185449" added
Restore Backup:
%windir%\system32\inetsrv\appcmd.exe restore backup "Backup1"
List all backups:
%windir%\system32\inetsrv\appcmd.exe list backups BACKUP "Backup1" BACKUP "20180204T101820" BACKUP "20180204T104714" BACKUP "20180204T104716"
The backed up configuration files are placed in: C:\Windows\Sysem32\inetsrv\backup