Can I place GTC orders on Kite?
Good till Cancelled (GTC) orders are currently not available on Zerodha.
However, you can use Sentinel to create alerts for the stocks that you wish to buy/sell at a specified price. This alert will remain active until it is triggered. Check out this post to know how.
The basic plan of Sentinel will remain free for all users that allow for the creation of 30 triggers on the Last Traded Price (LTP)
Read more on Sentinel here.