To add a new account to your Outlook, click File at the top left of Outlook
Then inside the File menu, click "Add Account"
A new window will now appear asking you for Your Name, email address and password.
Once you have entered your details, click next.
Outlook will now begin to configure your account, and just before it is able to finish there
will be a Windows Security window pop up.
Check the "Remember my credentials" checkbox and enter your password again.
Now click "OK"
Once you have clicked OK there may be another Window pop up asking you to allow or cancel.
Check the "don't ask me about this site again" box and click "Allow".
You should now see 3 green ticks on the Add Account window.
You will also be notified to restart Outlook.
You can now click OK, and then finish.
Close down Outlook and re-open it, you may be asked to enter the Windows Security again.
Just ensure that "Remember my credentials" is checked and this will store your password.