If you have someone's phone number in your contacts, it means they're in your WhatsApp contacts if they use the app.
Ọ bụrụ na i nwere nọmba ekwentị na kọntaktị gị, ọ pụtara na ha abanyelarị na kọntaktị gị na WhatsApp ma ọ bụrụ na ha na-eji ngwa ahụ.