Hello, thank you for reaching out to Microsoft Q&A.
Unfortunately, there is no built-in option in Windows 11 to switch to or fully customize the Start menu to look like the classic one (Windows 7 style).
However, you can find some options under Settings > Personalization > Start, where you can customize a few Start menu behaviors and layout preferences.
To use a classic-style Start menu, you will need to use a third-party utility such as Open-Shell to customize the Start menu layout.