Crescendo for both Treble and G clef

Hi ,
I am not quite if I add it a crescendo to the middle between the 2 staves (G,F) that will be applied to both notes on both clefs ? Any ideas ?

Yes, dynamics applied to the top staff of a grand staff system will apply to both by default.
I think you can use alt-enter to enter voice-specific dynamics. (Both staffs being different voices by default).

I am using that dynamics for piano . Can you explain please how can I use alt-enter to enter voice-specific dynamics?

If you enter dynamics vis the shift-D popover, confirm not with enter but alt-enter

Here are instructions for inputting dynamics with the popover - the note in step 1 clarifies what to do if you want to input voice-specific dynamics, and step 5 gives you the choices of “all voices” or “current voice” using Alt/Opt-Return as @klafkid described above.