Navigate to the handbook page for MuseScore 2: Barlines
Change bar line type
Bar lines are changed by dragging a bar line symbol from the bar line palette to a bar line in the score.
To hide a bar line entirely, right-click on the line and choose Set Invisible.
Create grand staff
To extend bar lines over multiple staves, double-click on a bar line to edit it (see Edit mode ).
Click and drag the blue square down to the next staff.
Staff bar lines updates appear when you leave edit mode.