You can use multiple templates with different paper formats (squared, lined, etc. ) on your documents:
1- Open two windows of Notes Writer on your iPad
2- Go to the "Templates" location on the left window and tap on a template to create a document based on it
3- Once opened the new document, tap the "+" button the choose "Document Editor"
4- On the right window, go to the "Templates" location and choose a template, drag an drop that file directly on the left window
5- You will see how the new template is inserted on your document. See attached screenshot. ;)