Hi Hossam Moussa,
Thank you for your patience. Currently, direct validation of digital signatures in the Angular PDF Viewer is not supported by default. However, this functionality can be implemented at the application level using the Syncfusion PDF Library.
We have attached a sample and provided a demo link for your reference. Please review them and let us know if they meet your requirements or if you have any questions.
Sample browser link
Client Sample
Web Service Sample
Steps to run the application:
1.Run the Web Service Sample
2.Run the Client Sample
Regards,
Venkada Subramanian D