What is office 365 theme?
You can customize the look and feel of your office 365 portal by choosing the multiple themes available in your office home page settings. Theme would appear in both “Dark” and “Light mode“. Themes settings would be honor by all office apps including yammer, One drive, Outlook Web, and Planner. Few apps that don’t use M365 themes are Sharepoint classic view and Teams Web/client (an Electron-based app) and always use their own interface elements.
Themes selection by End-Users
You can see several themes listed in the below screenshot but if you can only see 1-2 high contrast themes in your office home page theme settings, then it’s disabled by admin (yeah, it’s possible :).
Themes settings by Office 365 Admins
Office/Microsoft 365 Administrator can control the settings of themes for the entire organization. Admins need to have a “Global admin Role” for making the change. you need to go into the admin center, go to the Settings > Org Settings page, and then choose the Organization profile tab and select the custom themes.
There is a total of 5 themes that can be created (1 default + 4 custom). Organizations can also force end-users to use the ORG-specific themes by replacing the default themes with new themes and enable the settings “Prevent users from overriding their themes” under the default option.
Now go ahead and use the super cool themes available before your admin disable it for you 🙂 !!!