Add backup.create service (#22407)

* Add backup.create service

* Tweak

Co-authored-by: H. Kamran <hkamran@unisontech.org>

Co-authored-by: H. Kamran <hkamran@unisontech.org>

source/_integrations/backup.markdown

@@ -31,3 +31,38 @@ You need to restart Home Assistant after you add this configuration.
 When it has started up again you will find a new "Backup" entry in the main menu (**Configuration** -> **Backup**).
 
 The backup files are stored in a new "backups" subdirectory in the root of your configuration directory.
+
+## Services
+
+The backup integration exposes a service that can be used to automate the backup
+process.
+
+### Service {% my developer_call_service service="backup.create" %}
+
+The {% my developer_call_service service="backup.create" %} service can be used
+to create a backup for your Home Assistant instance. 
+
+The service has no additional options or parameters.
+
+Example service call:
+
+```yaml
+service: backup.create
+```
+
+## Example: Backing up every night at 3:00 AM
+
+
+This is a YAML example for an automation that initiate a backup every night
+at 3 AM:
+
+```yaml
+automation:
+  - alias: "Backup Home Assistant every night at 3 AM"
+    trigger:
+      platform: time
+      at: "03:00:00"
+    action:
+      alias: "Create backup now"
+      service: backup.create
+```