Hello,
There are two ways to enable/disable automatic opening of apps/items at login:
1. Open an application, click and hold on its icon in the Dock, choose Options from the pop-up menu, and select Open at login. Follow the same steps to remove the checkmark to remove it from Login Items.
2, > System Preferences... > Users & Groups > your user > Login Items > click the + plus button and navigate to the application/item, click once to highlight, then click Add button - or click and drag an application from another Finder window into the Add window. Highlight the application in the Login Items window and click the - minus button to remove it.
Let us know if that works for you.
C