The Scheduling Poll feature is a feature that is included on everyone's outlook program and web portal. This feature helps find available meeting times among the various meeting participants based on their calendars, then builds consensus by allowing the participants to vote on the best meeting times, and then sends out the meeting invite on your behalf.
Below is the location of the feature on the outlook bar of all versions of outlook:
Current App Version
New App Version
Web Version
To schedule a poll, fill out the "To" field in the new email page with the individuals you would like to have the meeting with, then click on Scheduling Poll. Once you click on it, the screen below should appear:
This screen will show common times that all of the individuals will be free, according to their outlook calendars. You can then select a few times to initially propose when you send the scheduling poll, although these don't have to be the only times that will be discussed. Individuals can either vote or propose a new time for the meeting when you send the poll. Once everyone agrees on a time, there will be a calendar event that will be made for all the individuals at the time and date they agreed on.
Below is also a GIF demonstrating the process.
Click here for the official Microsoft guide on the feature.