1. Foremost, we need to activate the developer mode.  In the main menu; Settings---> Developer Tools. 

2. Then in the main menu, we type "Paper Format" and select the first option.

3. Then we create a new format, in this menu we can specify the measurements needed. For example, the paper size, margins, etc. We can even choose an associated report so every time we use this report the format we just created applies to the type of paper.