Your questions

📄️ Adding a bot to a Telegram channel with more than 200 subscribers

Only the channel owner can add a bot if the channel already has more than 200 subscribers. An administrator does not have such rights.

📄️ Plugin bot uses WebHook

Unfortunately, the bot cannot be used to join a group.

📄️ Why is a post published under the name of a bot and not a channel?

If a post in Telegram appears to be from a bot and not a channel, this is due to the way Telegram works and the differences in the interface display across its versions.

📄️ How to publish voice messages?

To send a voice message: