You can’t as it is not supported through Wix Chat app.
Please note that if you require more help about the Wix Chat app, then you would be better suited going through Wix Support or reading their own support pages for the app itself.
https://support.wix.com/en/article/contacting-wix-customer-care-for-support
https://support.wix.com/en/ascend-by-wix/wix-inbox-and-chat
Wix Chat feedback.
https://www.wix-crm-feedback.com/
If you are using the Wix Chat app with Corvid, as shown below, then we can help you here as this Corvid Forum deals with all code related issues.
https://www.wix.com/corvid/reference/$w.Chatbox.html
https://www.wix.com/corvid/forum/corvid-tips-and-updates/example-corvid-chat/p-1/dl-5e1b2dc807c1a200179327fa