I’ve been using Google Docs API to create a templating platform where admin add a google doc which has placeholders. The user later fills the placeholders (in frontend as a questionnaire) and the document is generated from backend.

Now, I have also added subscriptions to the platform meaning if user does not have subscription, the preview has to have a watermark. I want to achieve this dynamically using google docs API .

I have had a few alternatives but these are not the prefect solutions:

1. Create Header and Footer using the API but I require a background text rather than just a header, footer.
2. Create a separate google doc just for free users but here the admin would have to manage the content in 2 docs so I need something that can be done dynamically using APIs.