Adobe Portable Document Format (PDF) is a versatile file format that can represent both vector and bitmap data. You can bring artwork from PDF files into Illustrator using the Open command, the Place command, the Paste command, and the drag-and-drop feature.
Use the Place command with the Link option selected to import a PDF file (or one page of the PDF if it is a multi-page document) as a single image. You can modify the linked image using transformation tools; however, you cannot select and edit its individual components.
Use the Open command or the Place command with the Link option deselected to edit the contents of a PDF file. Illustrator recognizes the individual components in the PDF artwork and lets you edit each component as a discrete object.
Use the Paste command or the drag-and-drop feature to import selected components from a PDF file, including vector objects, bitmap images, and text.