The Mail app doesn't support POP (Post Office Protocol) accounts. To set up a POP account, other options are available from Microsoft.
From the Start screen, tap or click Mail.
Utilize the touchscreen (if available) or mouse to select on-screen options.
If not available, do one of the following:
Swipe up (starting from the middle of the screen) to display the Apps screen then tap Mail.
Click the down arrow icon (located in the lower-left) to display the Apps screen then select Mail.
From the right edge of the screen, swipe left to display the charms menu.
If using a mouse, move the pointer to the upper or lower-right corner of the Start screen then move up/down.
Alternatively, press the Windows+C keys ( +C) located on the physical keyboard (if available).
Select Add an account.
Select the account type (e.g. Outlook.com, Google, Yahoo!, Other account, AOL).
Outlook.com includes Hotmail, Live, and MSN.
If presented, select IMAP then select Connect (located in the lower-right).
Selected when a radio dot is present.
Enter the appropriate email address and password then select Connect.
If account settings aren't auto-detected, the settings can be entered manually (begin with step 6).