What do companies use for desktopless employees without emails?
Many companies don't issue emails to frontline workers because of costs. What do they prefer to use? Text messaging or Whatsapp groups?
Depends on your situation, sometimes a WhatsApp group is enough, although there's always someone that doesn't have it (for reasons of their own, all are valid). What's your use case? You could make a case that pen-and-paper letters are a valid medium of communication if you're a notary, so tell us what you're looking for.