Sometimes it might happen that you have an empty page in a .pdf file. The reason for this can be found in this article.

Page break not necessary

With a 'page break' mark you ensure that a new page is created. Make sure you do not insert too many page breaks or just after a page too full as this often places the page break onto a new blank page.

Do not insert a page break at the end of a quotation/document

This in fact creates an extra page.

An empty page behind a cover sheet

You do not have to create a page break after a cover sheet since the page is already fully filled in.