First open the PDF to be identified, and click Edit->; Edit text and images option to perform OCR recognition. Secondly, after completing the above steps, a single page will be recognized by default, but if you want to recognize the entire PDF file, just click the "Settings" button under "Scan Document" in the lower right corner of the figure.

Then, after completing the above steps, in the pop-up window, check the item "All pages can be edited", click the "OK" button, and then click the edit picture to identify the whole article. In this way, the problem is solved.