I created a preset on my desktop lightroom and I emailed it to someone to use, but they want to use it on mobile. The file is .xmp, so how can they use it on their mobile app? Does it have to be in a different format or are there different steps to making a mobile preset rather than a desktop preset?
I believe the recipient of your presets will need an active membership in an Adobe Photography plan to use the presets.
This web link has details for methods to sync presets with Lr Mobile-