easily replacing / removing&adding image or text in header

[Leonas2000]

I have a template that I want to fill out. Replacing dummy images and text like {{fill_in_with_variable}}. Is there an easy way to find a text in the document? I'm afraid that the placeholder might be split between runs or that there is extra text in a run. Thanks!

[Leonas2000]

So my use case is, I have a word document containing images and text that others fill out. I then have templates that I want to populate with the information from the other word file. So I need to 1. Find text and images following keywords. And then in the new template document finding keywords, deleting them and adding new runs or images.

[Leonas2000]

For now it would be enough to just know how to do it.
It would be nice to add an XML editing part to the documentation. I have a hard time finding out the structure of the program. Where are all the XML saved, and what could be useful to help finding tags. Not explaining lxml but how this project generates the structures.
Something that explains what the _blob, paragraph._p or _element etc. Different parts and how to access them. So like header1.xml is under sections. Or how to access relations and edit them. thanks!