Read string from PDF

Hi all,
I would like to extract some strings of text from a PDF file, in a few fixed positions.
Is there any possibilities?

I tried also to export PDF to JPEG and to apply Machine Learning and OCR, but something went wrong: probably the image of the document is too complicated to train di OCR Module. Is there a way to provide to the OCR Module the exact coordinates where to read?

If you have exhausted possible ways in AppSheet and using zapier, integromat etc. using code that can parse the PDF is the only way Iā€™m aware of.