Every open ended scheme offers liquidity with almost complete freedom, i.e. no restriction on time or amount of redemption. However, a few schemes may specify an Exit Load.
For example, a scheme specifies an exit load of 1%, if redeemed within 1 year. What it means is that, if an investor has invested on April 1, 2016, any redemption done on or before March 31, 2017 would attract a penalty of 1% on the NAV. If an investor redeems on February 1, 2017 with the NAV at ₹ 200, then ₹ 2 would be deducted and only ₹ 198 per unit would be returned to investor.
All information on exit loads are usually mentioned in relevant scheme related documents. For instance, a fund fact sheet or key information memorandum would contain such information.