Ask clients for their phone number in online chat-box

Is it possible to create a field in online chatbox to ask clients to leave their phone number?

Yes, the feature that allows to create additional field for chatbox in online status to ask customers to leave their phone number is available in Live Chat PRO plugin version.
Here is a guide how to do it:

  1. Login at your wp- account
  2. Move to Widget area

Live Chat app

3. Make sure that there is Online status in Chat Preview.
4. Find the field Custom additional fields, type the name of the field, e.g. Tel.number

5. Click on Add and then Save and activate. 

live chat plugin for site

6. After that there will appear newly created field (in our example it is Tel.number) in Chat Preview and on your website chatbox

live chat for website

Custom additional fields is also available for chatbox in offline status. More here