Keyboard shortcuts for Outlook - Outlook - Office.com
Start a send/receive for all defined Send/Receive groups with Include this group in Send/Receive (F9) selected. This can include headers, full items, specified folders, items less than a specific size, or any combination that you define.
F9
Start a send/receive for the current folder, retrieving full items (header, item, and any attachments).
SHIFT+F9
Start a send/receive.
CTRL+M
Define Send/Receive groups.
CTRL+ALT+S