This is done by creating your own tables in the database.
For example, the ps_custom_header table and the ps_custom_header_lang table.
Next, you can create a configuration form and a list of saved forms in the module.
And for that you will create your own tpl template and load into it a field saved from the database for a certain language.
I already gave you the link to the developer help in another post.
Find HelperForm and HelperList.