How to Request Files in Teams

To request files be submitted to a folder in Teams, navigate to the Team in question and select the channel:

Decide which folder the requested files should be submitted to, select it, and press "Request Files":

Then, either copy a link that can be used by anyone with access to it to submit files, or send an email directly to whoever you would like to be able to submit files:

Now, recipients of the link or email can submit files that will appear in the specified folder.