When you get messages from non-friends on Facebook Messenger, they go to a "requests" folder. The thing is, this folder isn't really easy to find, especially after Messenger's recent update to version 4.
The recent Messenger update is, in fact, supposed to "simplify" the experience, and truth be told, it has for the most part. But the requests folder? Nah. It's practically hidden now in a place that makes no sense to anyone at any time.
The good news is that once you know, you know. Here's how to find it
So, with Messenger open and on the main page, tap the little people-looking icon at the bottom.
From there, tap the other person-looking icon in the upper right corner
And it's in the top row: Requests
Why on earth Facebook thought the requests folder made sense tucked two menus deep is beyond me, but alas, there it is.