Added FAQ

FAQ.md

@@ -269,6 +269,7 @@ FairEmail follows all the best practices for an email client as described in [th
 * [(139) How do I fix 'User is authenticated but not connected'?](#user-content-faq139)
 * [(140) Why does the message text contain strange characters?](#user-content-faq140)
 * [(141) How can I fix 'A drafts folder is required to send messages'?](#user-content-faq141)
+* [(142) How can I store sent messages in the inbox?](#user-content-faq142)
 
 [I have another question.](#user-content-support)
 
@@ -2632,6 +2633,21 @@ You can fix this problem by manually selecting the drafts folder in the account
 If there is no drafts folder at all,
 you can create a drafts folder by tapping on the '+' button in the folder list of the account (tap on the account name in the navigation menu).
 
+<br />
+
+<a name="faq142"></a>
+**(142) How can I store sent messages in the inbox?**
+
+Generally, it is not a good idea to store sent messages in the inbox because this is hard to undo and could be incompatible with other email clients.
+
+That said, FairEmail is able to properly handle sent messages in the inbox.
+FairEmail will mark outgoing messages with a sent messages icon for example.
+
+The best solution would be to enable showing the sent folder in the unified inbox
+by long pressing the sent folder in the folder list and enabling *Show in unified inbox*.
+This way all messages can stay where they belong, while allowing to see both incoming and outgoing messages at one place.
+
+If this is not an option, you can [create a rule](#user-content-faq71) to automatically move sent messages to the inbox.
 
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