If you use Microsoft 365 Defender Advanced Delivery this guide will make sure emails make it to the inbox.
Configuring Advanced Delivery is done through the Microsoft 365 Defender Portal.
To view step-by-step instructions on setting up the Allowlist in Microsoft Defender, please view the following Allowlisting Guide.
Resources
The source of truth document on the Microsoft side is:
https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/configure-advanced-delivery
Safe Links
If you are attempting to stop Microsoft from detonating your simulation URLs, which counts as a user clicking on the link, then Advanced Delivery can be used.
Quoting the “Configure the delivery of third-party phishing simulations” document above
“Safe Links in Defender for Office 365 doesn't block or detonate the specifically identified URLs in these messages at time of click. URLs are still wrapped, but they aren't blocked.“