Currently in Office 365, there is a setting that allows users to personalize what page they land on when they log into Office 365. The Office 365 Home Page has evolved to pull a user’s most relevant apps, documents and places where they are working all in one place and consequently will be the default page a user lands on when signing into Office 365.
Gradually rolling out in March 2019.
Initially designed start page setting to bring users to a preferred app faster. Now that the Office 365 Home Page has evolved to provide quick access not only to default and recently used apps but also recent and recommended files and places, option to select a different default start page will now be retired. Of course, users can continue to leverage browser bookmarks and direct URL navigation to apps like Outlook to get straight to the app of their choice.
In March, users who have set a start page other than the Office 365 Home Page will be directed to the Office 365 Home Page upon log-in.