No, it isn't for voice. Whenever you send a message in minecraft, it makes a bot send that message in a telegram group. When someone sends a message in telegram, it appears in the game chat.
P.S. sorry for not checking back for a few days
MutualChat is a plugin to connect a telegram group and the chat on a Minecraft server.
The creator only tested it in 1.13, but I put it on a local server witch was on 1.16.5 and it worked great.
the link is https://www.spigotmc.org/resources/mutualchat_telegram.64670/