Yes, these mobile devices like iPhones, Androids, and other tablets can use many popular Voice over IP phone providers without issue. Since 4G and 5G cellular signals are widely available with comparable speed to wired broadband, mobile phones act as additional VoIP devices. To use your cell phone with VoIP, download the recommended softphone app, sign in with your credentials, grant it any permissions asked, and you're all set to enjoy phone calls entirely over a Wi-Fi or cellular connection.