With the PDF Import premium feature you can import a PDF into Squid as a new note and easily write, draw, and markup on the PDF just like a standard note. A PDF is displayed as the background of a note in the original PDF format, so zooming in re-renders the PDF (as well as all your handwritten notes) in high quality. If you want to share your marked up PDF note with others, simply export it as a new PDF or set of images. Exporting a PDF note as a new PDF preserves the original PDF while adding all your handwriting and markups to it!
The highlighter tool is also included in the PDF Import premium feature.
The PDF Import premium feature is part of Squid Premium, or can be purchased as an in-app purchase within Squid.
If you're missing premium features you've already purchased, please read My premium features are missing! What happened?
For a video tutorial about PDF Import, see Squid - Working with PDFs.