How can I "require" a signature?

[system]

Hello, I’m Ron, an automated tech support bot

While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:

Guides:

• PDF.js Express Plus Overview - Select an integration or framework to get started - Frameworks
• Manually Download & integrate PDF.js Express Plus - Run samples
• Signatures with PDF.js Express - Get started

APIs:

• Core.Annotations.Forms.Field - new Field(name [, options])
• PDF.js Express Utilities
• UI - setSignatureFonts(fonts)

Forums:

• Is there an event for when signatures get placed onto a PDF?
• Is there a limit to the number of documents I can send to be signed by my customers per month?
• Revoke the possibility to change the signature placeholder location by the end user