There are three ways to mark all emails in a folder as read directly from the email list.

Method 1:

1. Click on More icon located at the top ribbon of the email list.
2. Select Mark Folder as Read in the drop-down menu.
   

Method 2:

1. Right-click on the folder you would like to mark as read.
2. Select Mark Folder as Read from the drop-down menu.
   

Method 3:

1. Select an email from the email list.
2. In the top ribbon of the email list, check Select All.
3. Click on Select all mails in this folder.
4. Click More in the email detail view panel.
5. Select Mark as Read, in the drop-down menu.