End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
http://slidesaaz.farafile.ir/file/30766/فصل-سوم-کتاب-اقتصاد-مهندسی--معرفی-و-کاربرد-فاکتورها