When you go and octave higher on the piano do write it same if were an lower when are composing a song?

In music notation, when you want to write a note an octave higher or lower than it would normally be written, you use an 8va (ottava) or 8vb (ottava bassa) symbol.

- 8va (ottava): This symbol means "play the notes an octave higher than written". It is placed above the staff, and it affects all notes until it is cancelled by another 8va symbol or a natural sign (♮).

- 8vb (ottava bassa): This symbol means "play the notes an octave lower than written". It is placed below the staff, and it affects all notes until it is cancelled by another 8vb symbol or a natural sign (♮).

So, if you want to write a note an octave higher on the piano, you would write it in the same way as you would if it were an octave lower, but you would place an 8va symbol above the staff.