Yes, you can place After market Orders (AMOs) in smallcase for the below set of order types.
The orders will be executed at the current market prices.
Once you place any order after the market hours, you will get the below message before confirming the order.
And the order will be in pending status until it gets executed. So, you will also have the option to cancel the Placed order from the Orders page > Select the recent placed order > Cancel this order > Cancel Order:
Note: Please maintain a surplus cash of some additional amount in your trading account in case of placing Buy / Invest more / SIP orders. This is to ensure you have enough funds to purchase all the stocks instantly in case if the stocks price hiked up.