The Softfork is
a change in the cryptocurrency protocol that does not require a software update. Those nodes that have not accepted the changes can still interact with nodes using the new rules.
The Hardfork is
a change in the blockchain protocol, in which nodes that have accepted the new rules are unable to interact with nodes that have refused to accept them. This leads to the branching of the blockchain. As a result of the hard fork, cryptocurrencies Bitcoin Cash, Bitcoin Gold and Bitcoin Diamond appeared.