You can create templates that are marked as "Sub Templates" in order to use their content in other templates. This feature is especially useful when a common markup is needed on multiple templates (such as signature, header).
Creating Sub Templates
A template must be marked as "Sub Template" in order to be available for insertion in other templates. This can be done either at the time of creating a new template, or after - just look for a toggle or checkbox that marks the template as a sub template.
Using Sub Templates
To add a sub template to an existing/new template, locate the "Insert Sub Templates" option within the template editor. Depending on the version you