plugins/admin/admin.py

from pyrogram.types import (InlineKeyboardButton, InlineKeyboardMarkup)
from config import *
from pyrogram import Client, filters

@Client.on_message(filters.private & filters.user(ADMIN) & filters.command(["warn"]))
async def warn(c, m):
    if len(m.command) >= 3:
        try:
            user_id = m.text.split(' ', 2)[1]
            reason = m.text.split(' ', 2)[2]
            await m.reply_text("User Notfied Sucessfully 😁")
            await c.send_message(chat_id=int(user_id), text=reason)
        except:
            await m.reply_text("User Not Notfied Sucessfully 😔")