How to Whitelist an Email
How to Whitelist an Email in Gmail
1. Open the Gmail application.
2. Navigate to Spam or Junk Folder.
3. Click on the message you wish to view.
4. Select the option "Report not spam".
5. You will now receive messages from this sender as normal.
How to Whitelist an Email in Outlook
1. Open the Outlook application.
2. Navigate to the Junk E-mail folder.
3. Right click on the message you wish to view.
4. Scroll down to "Junk".
4. Click on "Not Junk".
5. Click "OK"
5. You will now receive messages from this sender as normal.
How to Whitelist an Email in Yahoo
If you want to move a sender or domain name to your whitelist Yahoo Mail, the process is easier than it is in the other service providers mentioned above.

As long as you have already received at least one message from the address in question, all you have to do is highlight that message in the Bulk folder and mark it as Not Spam. Once you have identified a single message from a given sender, the Yahoo Mail spam filters will automatically allow future messages from the same address into your inbox.
How to Whitelist an Email in Hotmail
1. Open your mailbox and click “Options” (upper right-hand corner).
2. Click the “Junk E-Mail Protection” link.
3. Select the “Safe List” link.
4. Copy and paste the email to be whitelisted into the dialog box titled “Type an address or domain”.
5. Click the “Add” button next to the dialog box.