If you want to delete archived messages on Facebook from your iPhone, there are a few different ways to go about it. The first way is to open the Facebook app and go to the Messages tab. Tap on the message you want to delete and then tap on the three lines in the top left corner of the screen. Next, tap on Delete Message. The second way is to open Facebook on your computer and go to your profile page. Click on Messages at the top of the page and then select All Messages from the dropdown menu next to Archive. Finally, click on Delete Message at the bottom of the screen. The third way is to open Facebook on your iPhone and go to Settings -> Messages -> Delete All Messages from This Device. ..
