1. Click the gear icon in Gmail and select "See all settings" from the Quick settings menu.
2. Navigate to "Filters and Blocked Addresses" in the top menu.
3. Select "Create a new filter."
4. Add a specific email or a whole domain in the "From" field.
5. Click "Create filter."
Simply click the Create filter button at the bottom of the window (next to the blue Search button).
6. Check "Never send it to Spam" in the checkbox.
7. Click "Create filter."
Once this information is specified, you click the "Create filter" button again, and this creates the whitelist within Gmail.
