Here is the working sample code to Place Orders:
from smartapi import SmartConnect
obj = SmartConnect(api_key="your_api_key")
data = obj.generateSession('client_id', 'your_password')
refreshToken= data['data']['refreshToken']
orderparams = {
"variety": "NORMAL",
"tradingsymbol": "symbol",
"symboltoken": "token",
"transactiontype": "BUY",
"exchange": "NFO",
"ordertype": "MARKET",
"producttype": "INTRADAY",
"duration": "DAY",
"quantity": "quantiy"
}
orderId = obj.placeOrder(orderparams)
print(orderId)
Above code just punch order and returns orderId of particular order.