Yes, you can. How you do so depends on how you want the content to appear in the building information plan.
If the desired content should be imported as a complete document in PDF format, a document within the building information plan should be used to import the file directly into the plan. See How do I import a PDF document into a Building Information Plan?
If the desired content should be imported as images (JPG format), the Import function (see images below) can be used to select pages from a PDF file and import them as images. The advantage of this approach is that the images can then be annotated within the mobile application. So if you have existing information like floor plans that need to be imported, you can use the Import function to bring them into existing plans. For a Step-By-Step guide to using the PDF Import tool, see How do I use the PDF Import tool in CityScape?
Note: You can also create new buildings using the administrative portal, and then import imagery. For creating new buildings in the admin portal, see Can I modify collected information (e.g. preplans, inspections) from the Admin Interface?