Click the Measure tool . A handle appears
on each barline.
Drag the top handle of the desired barline horizontally (there may be more than.
The measure becomes wider or narrower. If you move a barline in Page
View, you don’t just change the width of the measure whose right barline
you drag; you also increase or decrease the width of the measure to its
right, making this a useful technique for touching up your page layout.
(You can adjust all measures in a system except the last one with this
method.)