@dp.message_handler(commands=["start"])
async def cmd_start(message: types.Message):
poll_keyboard = types.ReplyKeyboardMarkup(resize_keyboard=True)
poll_keyboard.add(types.KeyboardButton(text="Codes Checker"))
poll_keyboard.add(types.KeyboardButton(text="Cancel"))
await message.answer("Click button Codes Checker to check the code!", reply_markup=poll_keyboard)
parse_mode
соответствующий режим работы