To add a feature request or vote on current ones, head to powerpoint.uservoice.com. Scroll to the bottom of the page to select the correct forum (PowerPoint for iPad, PowerPoint for Windows, PowerPoint for Mac, etc.), and post your feature request there. Then vote on the other posts you like. You get ten votes, so use them wisely!
For general Office suggestions, head to office.uservoice.com, and for the other apps just insert their names: word.uservoice.com, excel.uservoice.com, outlook.uservoice.com, onenote.uservoice.com, officemix.uservoice.com, sway.uservoice.com, onedrive.uservoice.com.
I’ve still got some votes left, so I’m looking forward to seeing your suggestions at powerpoint.uservoice.com! After you add your request on the uservoice website, post a link to it in the comments below so we know to vote on it.