Feature requests are open in the product rather than buried in a support inbox. You can browse what's already been asked for, add your own, and edit yours later.
Writing a useful one
The requests that actually get built describe the situation, not the solution. "Let me filter accounts by last activity" is a fine idea, but "I lose track of which accounts have gone quiet and end up working the loud ones" tells us what problem to solve, and we might solve it better than the filter you had in mind.
Before you file
Have a look at whether someone has already asked. Adding weight to an existing request is more useful than a second copy of it.