To enable Dark Mode in Microsoft Outlook, you can follow these steps:

1. Launch Microsoft Outlook on your computer.
2. In the top menu bar, click on “File.”
3. In the File menu, click on “Options.”
4. In the Outlook Options window, click on “General” in the left sidebar.
5. Under the “Personalize your copy of Microsoft Office” section, look for the “Office Theme” dropdown menu.
6. Open the dropdown menu and select “Black” from the options. This will enable the Dark Mode in Outlook.
7. Click on “OK” to save the changes and close the Outlook Options window.

After enabling Dark Mode, the Outlook interface will switch to a dark color scheme, providing a more comfortable viewing experience in low-light environments.

Please note that these instructions are specific to the desktop version of Microsoft Outlook and may differ slightly if you are using a different version or the web-based version of Outlook. Additionally, Dark Mode may not be available in older versions of Outlook, so ensure that you have the latest updates installed for the best compatibility and feature availability.