Startup Folder

Startup folder for your user account: This folder is located at C:\Users\[username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup.
Startup folder for all users: This folder is located at C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup.
The ProgramData folder is a hidden folder, so you will need to enable hidden files and folders to see it.

To open the Startup folder for your user account, you can use File Explorer and navigate to the following path:

C:\Users\[username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
To open the Startup folder for all users, you can use File Explorer and navigate to the following path:

C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup