on_member_left.py

import discord
from discord.ext import commands

bot = commands.Bot(command_prefix='!')

@bot.event
async def on_ready():
    print('Logged in as')
    print(bot.user.name)
    print(bot.user.id)
    print('------')

@bot.event
async def on_member_remove(member):
  print(f"{member} has left the server")

@bot.command()
async def hello(ctx):
    await ctx.send('Hello Friend')
    
    
bot.run(" Your Discord Bot Token")