If you have a large number of unread text messages in your Messaging app on iPhone or iPad, dealing with them one by one can be a problem. Fortunately, it’s easy to mark each of your unread messages as read in a snap, but the functionality is a bit hidden. Here’s how to do it.
First, open “Messages”. On an iPhone, look in the upper right corner of the screen and tap the ellipses button, which looks like three dots in a circle. (The iPad button is slightly different, as you’ll see below.)
On an iPad, tap “Edit” in the upper left corner of the screen.
In the menu that appears, press “Select messages”.
The messages will now enter “Edit” mode. But you don’t need to process individual messages just yet. On iPhone and iPad, look for the “Read All” button in the lower left corner of the screen. Tap on it.
After that, all unread messages will be marked as read. A piece of cake!