Get TELEGRAM Channel/Group ID

As of my experience ,there are two popular libraries,

python-Telethon            --->Telegram Client Library(uses api_id,api_hash) 
python-Telegram-bot        ---->Telegram Bot (uses api token)

There are lot of ways to get the user_id ,group_id,channel_id . To get the these ids use Telethon client library

from telethon import TelegramClient,sync
api_id="xxx" #get from telegram website
api_hash="yyy" #get from telegram website
client=TelegramClient(session_object,api_id,api_hash) 
client.start()
#To get the channel_id,group_id,user_id
for chat in client.get_dialogs():
    print('name:{0} ids:{1} is_user:{2} is_channel{3} is_group:{4}'.format(chat.name,chat.id,chat.is_user,chat.is_channel,chat.is_group))

That is all about, it will print name and id of channel,group,user. Also, it will check wheather the id is belong to channel or group or user

generally, Channel id starts with negrative(eg:-1001109500936) starts with (-100) group id is normal and starts with negative user id starts with positve

Another way is to use 'plus messanger app' To see all the group,channel,user id Cheers

Another Simple Way,

client=TelegramClient(session,api_id,api_hash)
client.start()
destination_entity_name="Type User(may be bot) or group or channel name"
entity=client.get_entity(destination_entity_name)
print(entity.stringify()) #All paratmeters
print(entity.id)       #user(bot also considered as user) or group

Invite your bot to your group

and use ur bot to text /myid

then use the GetUpdates api, you shall have your group ID