Begin by starting the desired Office 365 application Word, Excel or PowerPoint. When the application opens, you can find the search bar located at the top center of the title bar.
Go to “File” then select “Options” located towards the bottom left. For Word, visit the “General” tab then under the “User Interface Options” section in the right-pane.
To hide the search bar from the title bar, locate “Collapse the Microsoft Search box by default” option and check it then click the “OK” button at the bottom.
Once done, only a Search icon (visible as a magnifying glass) will appear in the application header.
I welcome your thoughts, questions or suggestions on my article on how to remove the Search bar from Word, Excel, PowerPoint in Microsoft 365.
Let me know if you found any errors within my article or if I may further assist you by answering any additional questions you may have.