how to raise melody 1 octave?

Via transposition: https://musescore.org/en/handbook/4/transposition

Select the melody line and press Ctrl+Up.

If the melody line switches from one instrument to another, you'll have to select the part of Instrument 1 that holds the melody and use Ctrl+Up to raise it one octave, then select the part of Instrument 2 that holds the next part of the melody and use Ctrl+Up to raise it one octave. And so on.

While you about it, you can lower any note or melody
by highlighting it and pressing the Down arrow.⬇︎

Control ⬆︎ to raise an Octave
(Command on Mac)
Control ⬇︎ to lower an Octave.
(Command on Mac)