Outlook: Add Safe Sender
Email addresses and domain names in the Safe Senders List are never treated as junk email, regardless of the content of the message. You can add your Contacts and other correspondents to the Safe Senders list to confirm you'll always receive their messages in your inbox.
By default, email addresses in your Outlook contacts are considered safe senders by the Junk Email Filter, but you can change this setting. Email messages from safe senders are never moved to the Junk E-mail folder.
Notes:
If you use a work or school account in Outlook, and your organization manages mailboxes in the Global Address List (GAL), these contacts are also considered safe senders. This doesn't apply to Contacts and Mail Users in the GAL.
When you send a message to a person or organization that isn’t an Outlook contact, the recipient's’s email address isn’t automatically added to the Safe Senders List. This means that when the recipient replies to your message, the reply message might be moved to the Junk E-Mail folder.