Telegram Groups, Supergroups, and Channels – A complete Guide

First thing first, what's the difference between groups, supergroups, and channels?
Telegram Groups are ideal for sharing stuff with friends and family or collaboration in small teams, they can have up to 200 members and by default everyone can add new people and edit the name and group photo.
If your group grows to a very large community, you can upgrade it into a more centralized supergroup. Supergroups can have up to 1000 members and have a unified history, deleted messages will disappear for everyone.

Channels are a tool for broadcasting public messages to large audiences. In fact, a channel can have an unlimited amount of members. When you post in a channel, the message is signed with the channel's name and photo and not your own.

Telegram groups are democratic by design. Everyone can invite new members and change the group‘s name and photo, which is ideal for small bands of friends or coworkers. But Telegram can also support much larger communities that need more administration. To make life easier in big groups, Telegram introduced “Admins” in its November 25, 2015 updates.

From now on, you can choose how your groups will operate. By default, all members are still in control. But if you want more order, you can throw the switch and appoint additional administrators to your group.

If you enable the new restricted mode, only administrators will be able to add new people and change the name and photo of the group. Admins also have the power to remove other members from the group.

Telegram Supergroups

Telegram groups have always been several steps ahead of the competition. You could have groups of up to 200 people communicating efficiently using replies, mentions and hashtags. Now it's time to go further.
Ever since our launch in 2013, our users have been telling us they would like to migrate even larger communities to Telegram. As of today, once your group is full, you can upgrade it to a supergroup that supports up to 1000 members.

Supergroups are optimized to host large online communities and will load quickly, even if you‘ve missed many messages while away. Here’s what you need to know about how they work:
* New members can see the entire message history when they join.
* Deleted messages will disappear for all members.
* Ordinary members can only delete their own messages.
* Supergroups are muted by default and send fewer joined/left notifications.

How to create Telegram group?

iOS: Start a new message (tap the icon in the top right corner in Chats). Then ‘New Group’.
Android: Tap the circular pencil icon in the chats list. Then ‘New Group’.
Windows Phone: Tap the “+” button on the bottom bar. Then ‘New Group’.

How to assign administrators in Telegram?

Telegram groups are democratic by design. Everyone can invite new members and change the group‘s name and photo, which is ideal for small bands of friends or coworkers. For larger communities that need more administration, we’ve introduced a special restricted mode.

In the restricted mode, only administrators can add new people and change the name and photo of the group. Admins also have the power to remove other members from the group.

iOS: Go to Group Info (tap the photo in the top right corner on the group‘s chat screen) — Edit — Add Admins. Disable ’All Members Are Admins' and appoint admins from the list.
Android: Go to Group Info (tap the name in the header) — … (in the top right corner) — Set Admins. Disable ‘All Members Are Admins’ and appoint admins from the list.
WP: Go to Group Info (tap the name in the header) — … (in the bottom right corner) — Set Admins. Disable ‘All Members Are Admins’ and appoint people from the list.

How to upgrade to a Telegram supergroup?

When your group reaches the members limit (currently at 200 users), it becomes possible to upgrade it to a more centralized supergroup that can get up to 1000 members. To do this, go to Group Info and choose ‘Upgrade to Supergroup’. This action is irreversible, sorry.

Things you may not like about your Telegram supergroup:
* There's no online members counter in the header. (for now)
* People in members list are sorted by last activity in the group, not by last seen. (for now)
* Ordinary members can only delete their own messages.
* Members can't invite new people, members can join via invite link or be added by admins.
* How to add more members In Telegram Groups? What's an invite link?
* You can add your contacts, or using search by username.

It is easy to migrate existing groups to Telegram by sending people an invite link. To create an invite link, go to Group Info — Add Member — Invite to Group via Link.
Anyone who has Telegram installed will be able to join your group by following this link. If you choose to revoke the link, it will stop working immediately.

iOS Bonus: Best In-App Notifications Ever
iOS users will enjoy our new in-app notifications. Pull down on a notification to expand it, view the full text of the message or preview attached media.

Quick reply from notification
You can immediately send a quick reply or a sticker — all without leaving that particular spot in some other conversation.

Android Bonus: Quick Share for Channels
Meanwhile, Android users can enjoy the new quick sharing menu in channels. Just tap on the forwarding buttons right next to channel messages.
The new sharing menu on Android

See Also:
How to Edit Messages on Telegram Messenger ~ Telegram Updates

Telegram Messenger Reordering Stickers and Clearing Cache
Telegram Messenger Custom Sticker Sets
Telegram Group Chats: Replies, Mentions, Hashtags ~ Everything you need to know
Telegram Messenger Stickers - Telegram MOAR Stickers!
How to self- destruct messages in Telegram?
Secret chat in Telegram? How to start secret chat in Telegram?
How to use or install Telegram Messenger App on Android?
Download Telegram messenger App for Android, iOs, Windows and Desktop 
How to install or use Telegram Messenger App on Desktop?   
What is Telegram Messenger App?
How to add or invite friends in Telegram?
Telegram Messenger Tips and Tricks