[alx__]

Literally the only reason to use Signal is to talk about unionizing, drugs, or shady biz deals.

Texting your coworker, would the usual path, not some secondary software that requires both people to set up ahead of time.

[monkeywork]

... sure ... "Literally" ... wow

You do realize there are many places in the world where WhatsApp is the defacto standard tool to communicate correct?