Your PDF's are in the correct format when they are in line with the below:
The maximum file size is 120 MB for PDF or overlay PDF.
Colors of PDF's made for print might look different on the iPad screen because the iPad iOS does not support the CMYK color profile which is common in PDF's for printing. For tablets, PDF's need to be in the RGB color profile.
PDF's created from PowerPoint or Word are already in RGB.
PDF's that come from graphical programs such as InDesign are typically made for print in CMYK. To change the color scheme you will need to export it with RGB from InDesign. To do this with Acrobat, you'll need to have the Acrobat Pro license.
d!nk does handle PDF documents with links as setup.
When adding links with InDesign or Acrobat, please make sure to point to links with exact page numbers. Relative links (for example: link to 'Previous Page') will not work correctly.
We do not support secured PDF's. To unlock your PDF, you can work with free online tools like: www.pdfunlock.com