You're able to define Placeholders and ImagePlaceholders in the Admin Configuration, which you can use in your template.
Each of them consists of a key and a value.
Placeholders are used in templates, can have a default value and can also be overwritten on a page by using an "OneOffixx Exporter Field Macro".
You can use placeholders in a template by choosing placeholder options from the dropdown menu, or just write the key into any textfield.
There are also some global default placeholders, which automatically get overwritten at the time of the export, like:
name of exported page
version of exported page
name of space of exported page
name of space key of exported page
name of user who started export
ImagePlaceholders are also used in templates. The difference between normal placeholders and imagePlaceholders is that imagePlaceholders are storing an image in Base64 format.
You can't overwrite them on a page, but you can use them in a template by using the key.