How do you make a Telegram channel public?

Channels are a tool for broadcasting public messages to large audiences. In fact, channels can have an unlimited number of subscribers. When you post in a channel, the message is signed with the channel's name and not yours. You can appoint additional administrators to help you manage the channel. New subscribers can see the entire message history in a channel once they join.

Public channels have a username. Anyone can find them in Telegram search and join. Private channels are closed societies – you need to be added by the owner or get an invite link to join. Please note that private channels with publicly available invite links will be treated in the same way as public channels, should it come to content disputes.

The owner of a channel can broadcast messages, delete any messages, add subscribers (the first 200 only), remove subscribers, change the channel's name, profile image and link, as well as delete the channel completely. The owner can also add and remove administators to help manage the channel. You can set up administrator rights for each individual administrator when you appoint them.

As of writing this, Telegram lets you add up to 200,000 members to your Telegram channel.