After Market Order (AMO) as the name suggests, is an order type that can be placed after the market is closed.  This order type is for people who cannot trade during normal trading hours. You can use AMO if you want to place orders for the next trading day after the market hours.  After Market Order Timings:

Product

Timing

Equity spot/cash Market

5:00 p.m. to 8:59 a.m.

Equity F&O Market

5:00 p.m. to 9:14 a.m.

Currency F&O Market

5:00 p.m. to 8:59 a.m.

Commodity Futures Market

12:01 a.m. to 9:59 a.m.