Do you have a feature you'd like to suggest to the Outlook product team? You can now make these requests in the Outlook uservoice at https://outlook.uservoice.com. You aren't limited to using it for Outlook desktop requests - there are sub-groups for all of the different Outlook apps from Mac Outlook, to the iOS and Android versions and even Outlook.com and Outlook on the web.
Because the requests with the most votes have a better chance of being implemented, make sure you search before posting. Read through the previously submitted requests and vote on your favorite ideas. If the request you were going to submit already exists, vote for it instead of making a new request.
The uservoice for Office 365, including the web apps, Delve, Skype for Business, and administration features, is at https://office365.uservoice.com.
Word, Excel, PowerPoint and Office in general each have their own uservoice. Each uservoice has separate forums for each version (Windows, Mac, iOS, and Android).