Help with missing ‘import preset’ button

@Weitingshyu 

If you bought a presets bundle for Lightroom Mobile from some 3rd party, instructions should have been provided on how to import.  Adobe also has a help document here: https://helpx.adobe.com/lightroom-cc/using/import-presets-mobile.html

As 'selondon' mentioned, Lightroom Mobile for iPhone/iPad can import presets by importing images with edits embedded in the file.  The edits can be saved out as a preset.  If the page above is not clear, try looking at other help from web searching "lightroom mobile import presets"

If you have some other form of presets, please clarify here but know that is probably served by Jim's advice.

If you have access to a desktop computer, you can use the Lightroom desktop app to import the presets and, assuming you are logged in using the same Adobe account details, the presets would automatically sync to LrMobile on your iPhone and iPad devices.

It's not missing as unfortunately on iOS it has never been there.

It's only currently possible (and has been for ages) on Android devices.

You can import a DNG and Create Preset from there, but guess that doesn't help you.