Templates are predesigned documents from which new documents can be created and then edited. Like a regular document, each template can contain its own pages/artboards, text styles, assets, swatches palettes and other resources.
Your Affinity app can import compatible templates with an .aftemplate file extension.
In order to create a document from a template, the template file must be stored in a location that is accessible in iPadOS's Files app, e.g. On My iPad or iCloud Drive, or a third-party cloud storage service such as Dropbox.
In the Files app: