Hi @Ashok_Shinde, all Custom Fields are Global, and therefor available to any project you create.
When adding Custom Fields to a Project, you should be able to click on “Add Existing Field to Project” which should bring up a dialog box where you can search for your Existing fields, such as Priority or Status.
Screenshot:
For more information, you can visit How to Create and Use Custom Fields in Asana | Product Guide • Asana Product Guide