ANSWER: Let’s start with the fact that your Lightroom Classic catalog is unique to Lightroom Classic. Installing Lightroom on your iPad, iPhone, Android phone, or even the same computer doesn’t impact your Lightroom Classic catalog; however, if you enable syncing in Lightroom Classic, any albums created in Lightroom will be synced to Lightroom Classic. To turn on syncing in LrC, click on the cloud icon at the top right and click Start Syncing. Any collections in Lightroom Classic that you enable for syncing will sync smart previews of any of those photos up to Lightroom Cloud and down to your mobile devices and Lightroom desktop. Any edits you make anywhere, will appear everywhere.