How do I change an email folder toolbar in Outlook 365?

[chuckmi]

We have a new corporate installation of Office 365. I'm now using Outlook 365 via a browser and outlook.office.com.

How do I change the toolbar icons above most email folders, like the ones in the red box below? I don't really use Snooze but I will use Mark as Read a lot. I poked around in the settings, did a search for an answer but did not find an answer.

The toolbar below is for the inbox.

Thank you!

[#2]

@chuckmi,  Settings > View all Outlook settings > Mail > Customize actions.

[#3]

Thank you Victor. Those options are for the reading message toolbar (toolbar that is to the right of the sender's name in each mesage), and composing a message toolbar, not for the inbox toolbar. And under the Quick Actions I have "Mark as read or unread" already checked and it does not affect the inbox toolbar.