Open ended schemes are open for subscriptions at all times whereas close ended schemes have a limited window of time when the scheme is open for subscription, at the time of NFO launch. Usually,close ended funds have a lock in period after which they become open ended. 

Close-ended schemes allow fund managers to invest the corpus with a long term view without the pressure of redemptions or short term results. Open ended funds, on the other hand, are liquid and accept subscriptions and redemptions anytime.