I am trying to extract product information from email receipts HTML. Most services I have found focus on OCR from paper receipts or PDFs. I would imagine that extraction of product information would be easier from structured HTML. What type of AI approach would be used to support this?
It depends on the data. If it is structured like form data, then you might not need AI at all — simple regular expression patterns might be fine. This would apply for example to address data. If you have the word street followed by a colon, followed by some text, it seems fairly obvious that this is the name of a street, and possibly also a house number.
If, however, you have free text, eg the answer to "describe any medical conditions you have", or "which companies have you worked at before?", then you might need to look at named entity extraction (NER) to identify names of medical conditions or companies.