how to delete a app which cannot be removed by finder and launchpad toggle?

If this Application is, like Apple Mail, News, Podcasts, Music, TV etc which are baked into the Operating System - they can not be Removed or Deleted by any means.

They can be removed from the Dock but the Application itself will still remain in the Applications folder.

Third Party Application is different matter. It is best to check with the Developer of the offending Application for their Specific Instructions for removing.

App installed by the system are protected, so they cannot be replaced by malware with the same name. It is not a good idea to uninstall them. You will not save much storage and it may cause problems, as the system expects the apps to be installed.

If you want to delete some apps installed by the system to reinstall them to fix a problem, the best way to do reinstall system applications would be to reinstall the system.

You should be able to delete it from the Applications folder.

Which app? Some apps installed by the OS cannot be easily deleted.