Since I am an Android and PC users some things may be different.
First enable sync in Lightroom Classic. You find that in preferences.
From your phones app store or play store install Lightroom mobile. Configure the app to allow sync, mine are
When I take a photo with the native or Lightroom camera they are available in "All photos". Now add them to your album.
Magically, if all is configured correctly, they are in Lightroom Classic in the collection. Expect some delay for the network to do it's thing.