Telegram is a cloud-based instant messaging and voice over IP service developed by Telegram Messenger LLP. It is a cross-platform messaging app for smartphones, tablets, and desktop computers. It is a secure, fast and free messaging and voice over IP service. Telegram is designed to be a secure, private and reliable service, with a focus on speed, security, and reliability. Telegram allows users to send messages, photos, videos, voice messages and documents of any type, as well as providing support for group chats with up to 200,000 members. It also features the ability to create channels, which are like group chats with unlimited members, and bots, which are automated accounts that can perform various tasks. Telegram offers end-to-end encryption for all communications, as well as two-step verification for added security. It also offers a self-destruct feature for messages, which can be set to a timer, for added security and privacy. Telegram also offers an optional cloud storage, called Telegram Cloud, which can store messages, media, and other data for up to two weeks, allowing users to access their messages from any device.
Signal uses open source, end-to-end encryption to keep your messages to another Signal user secure and private. It installs on your Android and replaces your default messaging app (On iPhone it's a separate app). It's very easy to use. You can still send messages to people who don't have it, but I recommend everyone to use it. Simple SMS messages are routinely recorded and stored forever without your consent. Signal combats that in a very user friendly way.