One method is to export the pin assignment information of the current project to a CSV file and import it into another project.
 
The method is as follows.
 
[How to export in the current project]
1. Make the current project's Pin Planner the active window and from the Quartus II menu bar
Select File → Export.
2. Specify the file name and press the Export button.
(A file called ****.csv will be generated in the specified directory)
 
[How to import in other projects]
1. Select Assignments → Import Assignments from the Quartus II menu bar.
2. Specify the exported csv file and select OK.
 
With the above, it is possible to migrate the pin assignment information of the current project to another project.
Please use PinPlanner, etc. to check whether the data has been successfully imported.