PDF is our preferred file format for receiving files. But please bear in mind that a PDF is essentially a wrapper for content, so any poor quality images will stay poor quality in the PDF. Bleed: If any content runs to the page edge, make sure a bleed value of 2mm or 3mm is set in the program being used. Some layout programs can produce PDF files directly by saving as a PDF or exporting as a PDF. Files can sometimes be printed to a PDF printer, and if crop marks/bleed are needed then the page size in the printer settings should be larger than the document size to allow for this. For documents where bleed is not an issue there are lots on online converting sites. Always check the PDF file with the original document. When making PDF files, please make sure all fonts are embedded. We use software which can change PDF files in all sorts of ways, but this is really designed for last minute small changes. Larger changes can sometimes be made and sometimes not depending on the complexity of the changes. Any substantial changes to a document should really be made in the original program followed by a new PDF being made. It is recommended to not have security passwords on PDF documents in case they do need to be edited.