Choose Left barlines > Display on Single
Staves and Display on Multiple Staves, as appropriate. Click OK. For
more information, see Document Options-Barlines.
Click the Measure tool ;
then double-click the measure you want to begin with a double barline.
The Measure Attributes box appears.
In the Left Barline row, click the Double barline
icon. Click OK. You return to your score, where Finale has drawn
a double barline along the beginning of the system.