you can use Azure Blob Storage to store PDF files and then
https://learn.microsoft.com/en-us/azure/storage/blobs/
then
use Azure Cognitive Search to index your Blob Storage
https://learn.microsoft.com/en-us/azure/search/
extract data from PDF files and index them
then
Write a script or application that queries the Azure Cognitive Search index and sends the results to GPT-4o for further processing.
https://learn.microsoft.com/en-us/azure/cognitive-services/openai/