There are a few ways to fix formatting in Visual Studio 2019.
If you have just installed Visual Studio 2019, you can launch the Visual Studio Installer from the Start menu and click the "Repair" button. This will fix any corrupt files and restore the default settings.
If you have made changes to the formatting settings and want to reset them back to the default, you can go to Tools > Options > Text Editor > All Languages > General. Here you will find an option to "Reset settings", which will reset all the formatting settings back to their defaults.
If you have installed an extension that is causing problems with the formatting, you can try uninstalling it and restarting Visual Studio.