Scheduling Assistant for Calendar Invites
Step 1: Create new invite
Within your outlook calendar double click on the day and time of the event you want to create
Complete the event title, add required attendee's, select time to and from.

Step 2: Scheduling Assistant
Select scheduling assistant from the top of the invite, this should show when recipients have availability
\
This will then show when everyone has availability and you can adjust your meeting time accordingly to suit all invitees.

NOTE: If you are using outlook in browser you will be presented with times where everyone is available.
