Automate PDF Merge & Indexing

I have a folder that receives multiple PDFs whose file-names carry key information separated by underscores. Typical segments include the PO number, Serial number, Date, Work order, Heat number, Calibration date and a few other identifiers. I need a Python solution that will: • Parse each file-name, isolate those data points, and write them into the specific fields of the document’s existing index (cover) page. • Concatenate the newly updated PDFs, preserving their order, into a single master file. • Drop that combined file into a fixed OneDrive or SharePoint location and return the cloud link. The script should be callable from a Power App / Power Automate flow, so clean parameter input and a straightforward command-line or API trigger are important. Use any robust libraries you prefer (PyPDF2, pypdf, reportlab, etc.) as long as the final code is readable and fully commented. Deliverables 1. Well-structured Python code with dependency list. 2. README that explains setup, variables for source & target folders, and how to hook the script into Power Apps. 3. A short demo (screenshots or video) proving the flow: file-name → field population → merged PDF in OneDrive/SharePoint. Acceptance criteria will be successful extraction of all underscore-separated values into the correct index-page fields and creation of the merged file in the designated cloud folder without errors.