If you’re renaming, type a new name, then press Return.
Custom templates always appear in My Templates in the template chooser. You can’t rearrange templates, and you can’t delete templates that come with Pages.
After you save a custom template you created, you can’t edit it. However, you can use it as the basis for a new template.
Choose File > New, then double-click the custom template you want to use as the basis for a new template.
Custom templates appear in the My Templates category of the template chooser. If you want to use a custom template that doesn’t appear there, you must first install the custom template (see the instructions above).
Make your changes, choose File > Save as Template, then choose an option to save the document as a new template.
You can delete the old template after you create the new one.
On your iPhone or iPad, you manage custom templates in the Create and use page templates in Pages on Mac