Can the HubSpot/Quickbook integration with JotForm capture signature fields?

if it can enable signature for clients within

Yes, JotForm can integrate with HubSpot and Quickbook. Quickbook can be integrated into JotForm via Zapier or Cloudpipes, however, Hubspot is available under the Integration option inside your form.

Related Guides:

https://www.jotform.com/help/551-How-to-Integrate-JotForm-with-Hubspot-CRM 

https://zapier.com/apps/jotform/integrations/quickbooks 

https://www.cloudpipes.com/integrations/jotform/quickbooks 

However, when you integrate the form with Hubspot, your form fields must match what shows up in your HubSpot account i.e. if there is a signature field in your Hubspot account.

Do review and get back to us if you have any further queries.