Dark Mode feature in Excel Worksheet (Grids) or O365 licensed users (Grides) and how to enable the dark mode theme
How to enable the dark mode to the excel worksheet in the O365 licensed users
Open the Excel --> In the View --> Dark Mode --> Click on Switch mode to Dark or White
How to change the interface to dark themes in the office
Go to the File option in Excel or Word --> More --> Account --> Find Office Theme --> Choose the required theme.