Telegram Bot: Poll in group

I am trying to create a Telegram bot that interacts in a group when a new user is added. So far, I am only able to send welcoming messages, but I cannot figure out how to send polls or other stuff. How can I do this?

My code:

import requests
import datetime
import time
import json

#Telegram imports
from telegram.ext import Updater # 更新者
from telegram.ext import CommandHandler, CallbackQueryHandler # 註冊處理 一般用 回答用
from telegram.ext import MessageHandler, Filters # Filters過濾訊息
from telegram import InlineKeyboardMarkup, InlineKeyboardButton # 互動式按鈕
import telegram

#  設定 token / Setting up token
token = '[[censored]]'
userId = '[[censored]]'

########### Welcome Function #########

def welcome_msg (item):
    chat_id=item["message"]["chat"]["id"]
    user_id=item["message"]["new_chat_member"]["id"]
    user_name=item["message"]["new_chat_member"].get("username",user_id)
    
    # Default Message:
    pollParam={
        "chat_id": chat_id,
        "question": "Black or White?",
        "options": json.dumps(["Black","White"])
    }

    # 初始化bot /  Bot initialization
    updater = Updater(token=token, use_context=False)
    print("Bot initilization done. The bot is now working in the group chat.")

    # Sending first message.
    welcome_msg=pollParam.format(user_id,user_name)
    to_url='https://api.telegram.org/bot{}/sendMessage?chat_id={}&text={}&parse_mode=HTML'.format(token,chat_id,welcome_msg)
    resp=requests.get(to_url)


######################################




endTime=datetime.datetime.now() + datetime.timedelta(minutes=3)

old_id=[[censored]]
print("Users:")
while endTime>datetime.datetime.now():
    time.sleep(1)
    base_url="https://api.telegram.org/bot{}/getUpdates".format(token)
    resp=requests.get(base_url)
    data=resp.json()

    # print(data)
    for item in data ["result"]:
        new_id=item["update_id"]
        
        if old_id < new_id:
            old_id=int(item["update_id"])
            
            try:
                if "new_chat_member" in item["message"]:
                    welcome_msg(item)
            except:
                pass

What is Telegram? Never heard of it. May need to supply a URL.

It’s a popular messenger. See here.