Adding an email address or domain to the Safe Senders list in Outlook will ensure that any emails from that sender will show up in your main inbox instead of your junk folder.
1. In the top right corner of the Outlook window click the three dots
2. Click Junk
3. Click Junk E-Mail Options
4. In the Junk E-Mail Options window click the Safe Senders tab
5. In the Safe Senders tab click Add...
6. Type in the email address or domain that you want to add and click OK
7. Click Apply and then click OK