How to configure your domain for Office 365 email
If you're adding a Porkbun-registered domain to Microsoft's Office 365 or Exchange Online, you'll want to update your domain's MX records to route mail to Microsoft's mail servers.
Log in. You should arrive at the Domain Management screen. If you're already logged in, click your username in the top-right corner and select Domain Management.
Locate the domain you wish to update. Click the drop-down list to the far right of the domain name. Then go to the section labeled "DNS Records" and select "Edit".
Scroll down to see your existing DNS records. If there are any existing MX records (look for "MX" in the leftmost column), delete all of them using the trash can icon.
Open up the following Microsoft support article in a new window or tab:
"Gather the information you need to create Office 365 DNS records."
Collect the TXT and MX values as instructed in the article, and make note of theme. You'll want to keep this information available while you make changes at Porkbun, so you can copy and paste the values.
Follow the instructions in this support article from Microsoft to create your TXT records and verify ownership of your domain at Microsoft:
"Create DNS records at any DNS hosting provider for Office 365."
To add the TXT/MX records specified, return to the "DNS Records" tab and scroll up the "configure custom DNS records" area near the top. Here's how to add an MX record:
A sample entry would look like this:
Click "Add" to add an MX record.
Repeat the above steps until you've added all records specified by Microsoft. Your MX records are now configured to point to Microsoft. These changes may take up to 48 hours to fully propagate across the Internet, although in most cases the change should be immediate.
Adding an SPF record
To ensure smooth email delivery, there is one final step you should undertake: Add a SPF record.
First, look for and remove any existing TXT records that contain the phrase "spf1"
Then, add one final record:
Change the Type field to TXT
Leave the Host field blank.
Under Answer type: v=spf1 include:spf.protection.outlook.com -all