I would first like to make clear that Outlook.com and Microsoft Outlook have very different functions and services. Although both can be used as the email clients for your domain email.

There are 2 ways you can do the implementation.

1. Straight a way, buy the email service from outlook.com or GSuite and use the email features by defining MX records in your Domain's dns manager. But this can be very costly over the time and over the number of users. Also, it gives you bundle of other services that you probably won't use. But still pay for them. If you want to go with this, go to link below and follow the steps. https://support.microsoft.com/en-ie/office/change-your-email-domain-in-outlook-com-premium-cc47f494-8679-4365-97c1-e709aebf727e?ui=en-us&rs=en-ie&ad=ie

2. You can have 3rd party shared hosting with hosting side email accounts. And then connect it through POP3 or IMAP and SMTP to outlook.com's interface or Microsoft Outlook Interface. This is the cheaper way to implement. But in this way little delivery delays might there while receiving there according to the frequency of email check requests.

If you want to go with this way, then first buy the hosting package with email and then follow the steps in the link below: https://support.office.com/en-us/article/add-your-other-email-accounts-to-outlook-com-c5224df4-5885-4e79-91ba-523aa743f0ba

Let me know if you want more information on this.