A: Hello, if you are using it on a computer, after opening the PDF document with UPDF, you can use the search function by clicking the magnifying glass icon in the upper right corner. If you are using it on a mobile device, click the flower icon in the upper right corner, then click the magnifying glass for text search. However, please note that our product currently does not support the replace function. You can look forward to our future updates. Thank you for your inquiry, and if you have any other questions, please contact us via email at support@superace.com.