Question

Notion iOS: I have a piece in B, the trumpet-voice appears in the key of C#, but I want it in Db (less accidentals). How can I manage to change the key for only the trumpet-voice?

Answer 1

When you choose the key signature tool from the 4th pane from the right in the palette, there is an option to "Enter for all staves."  If you de-select this option, the key signature will only be added to the selected staff.