Having the option to add a PDF in a Create & Print project

We need to have the ability to upload a PDF to a Create & Print "Upload Your Own Design" project. My daughter is a Graphic Designer and when designing something saves it in a PDF format instead of JPG because a PDF is a much higher resolution. We had to print her wedding invites elsewhere because when converting to a JPG to use in Create & Print they did not print clearly. We specifically had issues with text looking pixelated when printed. It’s standard practice for print shops or professional printers to use PDFs. It seems like the software might be compressing images when uploaded and therefore losing resolution. Therefore, it would be to our advantage for Create & Print projects to accept both PDFs and JPGs. 

Thanks for your consideration!