You can customize master pages according to your needs in the master page editor. Changing a master page affects the appearance of all layouts that use that master page.
Note
You must specify the page size, margins, page orientation, and staff size of layouts on the Page Setup page in Setup > Layout Options.
Procedure
In the Pages panel, double-click a master page pair in the Master Pages section.
The master page editor opens in the music area.
In the master page editor, change the layout of one of the pages of the selected master page pair. For example, you can change the size and shape of frames.
Optional: If you want both the left and right pages to be the same, click one of the following Copy Page Layout buttons at the top of the music area, depending on which page you changed:
Left to Right
Right to Left
Note
This copies the master page layout exactly from one page to the other, not as a mirror. For example, text frames for page numbers are not kept on the outside edge automatically.