This feature is available in Enterprise and Ultimate editions.
To access the portfolio item Templates page from the main menu, select Portfolio Planning > Templates.
To access the story/defect Templates page from the main menu, select Product Planning > Templates.
Templates should be created in the projects in which they will be used. The list of templates you see will be all those in your currently selected project and below in the project tree. Use the copy function if you need to have a similar template in different projects.