Streamer Mode is a feature allowing you to protect your privacy both in-game and out, by not allowing third-party apps to retrieve your Riot ID. 

This feature does not hide your Riot ID from your Friends list. Additionally, it does not affect the report behavior if you have this feature enabled.

How it works 

League of Legends/TFT

You can find Streamer Mode in League Client Settings → General → System. You have 3 options:

• Hide Other Player's Names - Hides the Riot ID of all the players in the match and replaces it with the champion name.
• Hide My Name - Hides your Riot ID from the other players in Champion Select Lobby, Loading Screen, and in-game, but only for the duration of the match. Match History and Replays are not affected.
• Hide My Identifying Info - Hides your Riot ID, progression, and achievements from all other players during Champion Select Lobby, Loading Screen, and in-game, but only for the duration of the match. Match History and Replays are not affected.

VALORANT

You can hide your Riot ID by going to VAL Settings → General Tab → Privacy Section. Your options are:

• Hide your Riot ID from players outside your party
• Use generic names for players outside your party