Display signature field in a document

Hi,I'm developing an application graphometric signing with vb net.
How can I view the signature fields in a document so that the user can sign them?
Can you provide me a code example?

To iterate all the fields see this sample code.
https://www.pdftron.com/pdfnet/samplecode/InteractiveFormsTest.vb.html

To add a digital signature, see this sample
https://www.pdftron.com/pdfnet/samplecode/DigitalSignaturesTest.vb.html

If you are looking for more information, please clarify your use case/user story.