Tap the Messenger app icon, which resembles a blue speech bubble with a white lightning bolt in it. This will open a list of your current conversations if you're logged into Messenger. If you aren't logged into Messenger, enter your phone number and password when prompted before continuing. Tap a conversation that contains messages that you want to delete. You may have to scroll down if the conversation is old.  If Messenger opens to a conversation that you don't want to review, first tap the "Back" button in the top-left corner. If you don't see your conversations listed, tap the Home tab to open the list of conversations. Find a message that you want to delete, then tap and hold it. A menu will pop up. On iPhone, this menu is at the bottom of the screen, while Android users will see a menu window in the middle of the screen. It's an option in the menu. Doing so will delete the message from your side of the conversation, though the person (or people) with whom the conversation is will still be able to see the message. If you just want to delete an entire conversation on mobile, do the following:  Find a conversation that you want to delete. Tap and hold the conversation until a pop-up menu appears. Tap Delete Conversation (iPhone) or Delete (Android). Tap Delete Conversation when prompted.
फेसबुक मैसेंजर एप आइकॉन खोजें: किसी एक चैट को चुनें: मैसेज पर टैप करें और उसे दबाकर रखें: Delete पर टैप करें: पूछे जाने पर Delete टैप करें: एक पूरी चैट डिलीट करें: