So on the Year of 2020th I decided to create my own FPDF-based PDF Library or Framework. I then called it OrchardPDF since it is economic and based on sprouting gardens. It is currently Closed-Source for the meantime until I will establish my own Company called Technical Geek. Now since it is loosely based on FPDF, yes. It has a Password Protection Module and also there's a "Custom" Prompt when logging in into the PDF File with a Password. Once I release this as an Open-Source Community-based Library I will add documentations on how to use it. But for now, You'd have to rely more into the News and Features I will add into the Framework since it is currently unavailable. Maybe by Mid of 2022 or 2023 I will freely Open-Source a Partial Copy of it on Github found here: https://github.com/binarykorra/OrchardPDF

So thats it, Good Day everyone!