You can store your templates in a local package namespace. For this, you need to put your template package in a specific directory, depending on your operating system:
- Windows:
%APPDATA%\typst\packages\<namespace>\<name>\<version> - macOS:
~/Library/Application Support/typst/packages/<namespace>/<name>/<version> - Linux:
~/.local/share/typst/packages/<namespace>/<name>/<version>(or via the environment variable$XDG_DATA_HOME, see the above link)
For <namespace>, you can use whatever you want, but something like local or templates would probably be a sensible choice. Additionally, all your templates need a name and a version. You can then import a template from your Typst document via
#import "@<namespace>/<name>:<version>": *