Added FAQ

FAQ.md

@@ -394,6 +394,7 @@ Anything on this list is in random order and *might* be added in the near future
 * [(191) How do I download and keep older messages on my device?](#user-content-faq191)
 * [(192) How can I resolve 'Couldn't connect to host, port: ...; timeout ...;' ?](#user-content-faq192)
 * [(193) How can I import Outlook contacts?](#user-content-faq193)
+* [(194) How can I set up automatic deletion of old messages?](#user-content-faq194)
 
 [I have another question.](#user-content-get-support)
 
@@ -5389,6 +5390,31 @@ If you are looking to synchronize your Outlook contacts with the Android address
 
 <br>
 
+<a name="faq194"></a>
+**(194) How can I set up automatic deletion of old messages?**
+
+To set up automatic deletion of old messages:
+
+* Tap on the account name in the navigation menu (left side menu)
+* Long press the folder you want to set up auto deletion for, and select to edit the folder properties
+* Near the bottom of the properties screen, there is an option to enable auto deletion
+
+Messages in the trash and spam folder will be **permanently** deleted, and messages in other folders will be moved to the trash folder.
+
+Unread, starred and snoozed messages and messages younger than 24 hours will not be automatically deleted.
+You can enable auto deletion of unread messages in the receive-settings tab page (option *Delete old unread messages*).
+
+Note that it isn't a good idea to automatically delete recent messages, especially not for the spam folder because there might be legitimate messages in the spam folder.
+There is a button or menu item (depending on the screen size) in the top action bar/menu of the trash and spam folder to empty the folder.
+This way there is at least a visual check.
+
+Auto deletion will be done on a full sync only.
+For the inboxes, you can use *Force sync* in the three-dots overflow menu of the start screen.
+For other folders, you can long press the folder in the folder list of the account (*not* the navigation menu), and select *Synchronize now* in the pop-up menu.
+You can also pull down the messages list of any folder to sync it, and repeat this again within 30 seconds for a full sync.
+
+<br>
+
 <h2><a name="get-support"></a>Get support</h2>
 
 &#x1F30E; [Google Translate](https://translate.google.com/translate?sl=en&u=https://github.com/M66B/FairEmail/blob/master/FAQ.md%23user-content-get-support)