Final Draft 12 can import a PDF with a high degree of accuracy, including the title page. Use the File > Open command for this. If you have Windows, be sure to set the File of Type dropdown to PDF Documents so Final Draft can see PDFs in the File > Open window:
Information on upgrading is HERE.
Previous versions of Final Draft do not have the ability to import PDFs. Follow the directions below if you have Final Draft 11 or older.
1. Open the script in Adobe Acrobat Reader and go to Tools > Export PDF, then save the document to your Desktop as a rich text file (.RTF):
2. Open Final Draft and go to File > Open.
2a. Windows only: At the bottom of the Open window, change the Files of Type dropdown to Rich Text Documents:
3. Navigate the Open window to the Desktop;
4. Double-click the RTF file icon to begin the import. When you're prompted to import as Script or Text, choose Script.
Note that you may need to do some reformatting. More information on reformatting material imported from other programs is here: I imported a script from Word (or another program) and it's all messed up. How do I get it back in shape?