If you want to convert a webpage into a Portable Document Format or PDF then you do it easily using an add-on in Firefox.
Save as PDF is a cool Firefox add-on which lets you easily save web pages as PDF.
Check out these: XnView Extension
and Memory Fox
Steps to be followed to convert a webpage into PDF:
1. Install https://addons.mozilla.org/en-US/firefox/addon/220850/
by visiting it in your Firefox.
2. In this step you need to restart Firefox to complete the installation and then visit any webpage which you want to save as PDF file and then click on Save as PDF icon in the Firefox.
3. A dialogue box will appear “Save File”.Choose the option save and save it in your computer.
You cannot change the default settings of the add-on,if you want to customize PDF then should opt for the paid account at Pdfcrowd.With the paid version includes options such as page size,page orientation, margins,password protection, initial view and more.