How to Change Page Margin and Column Settings in Adobe InDesign
See Adobe InDesign: Tips and Tricks for similar articles.
If you made a mistake in your new document setup, you can easily change the margins and guides.
- Go to the A-Master page using either the page navigator at the lower left corner of the document window or in the Pages Panel. By making the changes to the master page, it will apply to all pages in the file, unless the None master has been manually applied. The default is that all pages in a document are based on the A-Master.

- Go to the Layout menu and select Margins and Columns.

- Change the settings and you're good to go.

