Please get rid of the pop ups notifications and switch to the native macOS style notifications.

It would be helpful to either completely move, or at least add a send button to the top bar when composing an email. When all of the actions except send are at the top it seems quite odd and confusing to have to go to the very bottom to actually send a message. Another idea is to possibly shrink the composure box so it isn't so far away.

After pressing the tab key to go out of the Subject field of a new email, please focus on the body of the email, not the Font and font size.

Current tab-key sequence: To --> Subject --> Font --> Font Size --> Body
Suggested sequence: To --> Subject --> Body

"View Source" was an important tool for looking at the source (headers, body, servers, etc.) of a received message. It was in the context menu (right-click) but is no longer there. I could not find it in the menus either.

Ooops - did we lose the 'Resend' option for sent messages?

Literally can't even use the new Outlook now since we rely on this

When sending an incorrect email add the ability to recall that email from all recipients as is possible with Office for Windows client.

With the new Outlook i'm not allowed to drag and drop e-mails from one mailbox to another and thus making a copy in that mailbox and folder.

Please update the search function and add the "search all mailboxes" function again. Search should also be automatic, no enter-hitting.

I know I can tap in open in new window, but having to press it everytime is tedious and prone to mistakes

With the New Outlook for Mac, you seem to have removed the functionality to right-click on an email and set a reminder/flag/due date for a mail item. Can you please return this functionality? I found it especially useful for items that I could not act on at the moment but needed to follow back up with.

Have the ability to send an email to a group E.g. Interest Rate Changes and instead of sending emails back have the ability to turn into a chat underneath and in Teams. Like how Spark email does it at the moment with the Discuss email feature.

Would also be good for internal conversations on calendar invites, if someone wants to propose a new time or add info to the agenda. The calendar invite could become a Teams chat and files and chat could start around that meeting.

Add support for voting buttons.

The ability to customise or use other keyboard shortcut schemes (e.g. Gmail) on the web app makes it 2x faster to process email. Please bring it to the desktop app!

In Outlook for Windows I can add a send delay to every message as a rule. I like doing this because it gives me an extra minute or more to change my mind about an email after clicking 'Send'.

The web version offers a 10-second delay, which is even better than nothing.

The web based outlook.com and the windows version of outlook 2019 and 365 both support alias support. Only the mac version does not support this. It would be very useful if such support was added.

There is no easy way to toggle the Sidebar, when extended/open, you need to go to the view menu but once collapsed/closed. there's a nice icon to extend it again.
This icon should always be visible to the user.