Open Mail and select the Settings gear icon on the bottom left-hand side.
Select Manage accounts on the right side.
Select Add account.
Select Yahoo! from the list.
Follow the on-screen prompts to sign in to Yahoo Mail; you need to enter your username and password.
Select Agree to give the program access to your Yahoo account.
Select Yes when asked if Windows should remember your Yahoo Mail password.
Select Done to close.
Change the Default Email Program in Windows
The quickest way to get to Control Panel in any version of Windows is through the Run dialog box; enter the control command via the WIN + R keyboard shortcut.
Select Programs, or skip this step if you don\'t see that option.
Select Default Programs.
Select Associate a file type or protocol with a program.
In Windows 10, select the icon under Email.
in Windows 8 and Windows 7, select MAILTO from the list and select Change program.
Select the email program that\'s using Yahoo Mail.