MuseScore -- Index -- Brackets
Remove
Select the bracket and press
Del
Add
Drag a bracket symbol from the bracket palette to an
empty space in the first measure of a system.
Change
Drag a bracket symbol from the bracket palette to an
bracket in the score.
Edit
Double click on a bracket to enter
edit mode
,
In
edit mode
you can drag the hight of a bracket to span arbitrary staves
of a system.