Is it possible to link an office 365 email account for sending invoices, not just google?

It's good to see you here in the Community, @Will2022.

At this time, using an office 365 email account when sending invoices in QuickBooks Online (QBO) isn't available. 

I can see that connecting an office 365 email account to send invoices in QBO is helpful to you and your business. However, QBO only allows you to send invoices from your Gmail address as of this moment.

For now, I encourage submitting feedback directly to our product engineers. They may look into this suggestion and consider adding the option in the future update. To send feedback, you can go to the Gear icon and select Feedback. Then, enter your suggestion and click Submit.

You might want to view all your sales transactions created in QBO. You can go to the Sales menu and select All sales. 

The Community forum is always open to help you again if you need further assistance sending invoices in QBO. Wishing you continued success, @Will2022.