To extract data you can actually do a few things, suppose you want to use the entire the pdf you can use read pdf activity. let's say you want some particular information then in that case you can just use string split method to extract data.
Another approach which is more sophisticated is applicable only if all your pdf are in a particular format, if that is the case use can use screen scraping or ocr scraping and scrape around your anchored texts, for example you have pdf with customer details and all pdf have name , number etc in same format then use name number text as the anchor to extract your variable information
hope this helps