We've known for a while that Facebook had planned to reintegrate SMS and MMS into its Messenger app for Android. Well, it's finally live, and it's pretty great.
In order to get SMS and MMS abilities in Messenger, you'll need to being running the latest beta release (126.96.36.199.70), which you can get in one of two ways:
Once you have the beta installed, you'll need to go into your Settings app to change your default SMS app. This menu is located in different areas depending on the device you have, so the easiest way to get there is to use the search option within Settings. Search for "default apps," then choose "SMS app" and set it as Facebook Messenger.
Once you've done that, go back into the Messenger app and you'll notice all your SMS and MMS conversation threads have been merged into your conversation list.
You can distinguish between Messenger and text messages using the icons; the former has the Messenger lightning bolt on blue, the latter a speech box on purple.
Best of all, Messenger's unique features can be used with texts. You can send stickers, voice memos, thumbs up, and even your location.
For someone like me that uses Messenger as my main messaging platform, SMS/MMS integration is clutch. One app for all my messaging, and it's feature-rich!