In below code, the input field in the HTML section is referring to the pega property FirstName in pyWorkPage clipboard page. While the default value present in the input field is from FirstName property from UserData Page.
**Define Page Name (UserData) in Pages & Classes.
Use one clipboard source for the field, not two different pages. In your custom HTML, bind the input directly to pyWorkPage.FirstName, and before the section loads, copy UserData.FirstName into pyWorkPage.FirstName using a data transform. This makes the value display correctly in the HTML and also lets Pega save the user’s update back to the case page. Do not keep the default value from UserData while the input is mapped to pyWorkPage, because that creates a mismatch. Once both display and save use the same property, the value will move correctly between the HTML file and Pega.