Show what’s on mobile phone? Something to listen with (6)
I believe the answer is:
appear
'show' is the definition.
(I've seen this before)
'what's on mobile phone? something to listen with' is the wordplay.
'what's on mobile phone?' becomes 'app' (mobile phones have apps installed on them).
'something to listen with' becomes 'ear' (you listen with your ears).
'app'+'ear'='APPEAR'
(Other definitions for appear that I've seen before include "Arrive" , "Surface" , "be published" , "Become visible like ghost" , "Seem - come into view" .)