Widget Display Rules help you to manage on which pages Callback Widget should be displayed.
Products & Settings / Callback Widget / Websites / Widget Settings - Widget Display Rules
The value of the display rules depends on the type of condition. For condition of type Regular expression the value can be as you understand a regular expression. To use this type of rule you should have some web development skills. The value of the rest of the condition types can be just string.
Let me show some examples. Suppose you want to show Callback Tracker widget only for those website visitors who came to your website from your Email Marketing campaign. In this case your can add utm tag to the advertising link, for instance
Display rule:
Rule name = utm_campaign
Condition = equals
Value = email_marketing
Another example, suppose you need widget to be displayed only on your Contact page having address https://yourwebsite.com/contactus.html:
Display rule:
Rule name = URL
Condition = contains
Value = contactus
Watch this quick video and learn how you can adjust your click-to-call Widget Display Rules.