When you try to send a new message before the allotted time, the send button will be removed from the screen, being replaced by a countdown and a warning that Slow Mode is active. The administrator, however, can send as many messages as he wants, regardless of time. Here's how to enable Slow Mode on Telegram, available for Android and iPhone (iOS).
Step 1. Open a group conversation and tap the cover photo to open the settings. Then tap Edit;
Step 2. Tap Permissions. Then locate Slow Mode and determine how long members will have to wait to send new messages.
Ready. When attempting to send messages in sequence, users will be warned that Slow Mode is active.