A cryptocurrency is a condition or an update that’s applied to the blockchain. It’s just like any other software where you get updates when new things are added to put that particular software.
Soft Fork: An update in the software which is backward compatible (example: iOS 10 – iOS 11, Youtube App).
Hard Fork: Update in the software which is not backward compatible (Playstation 3 and Playstation 4). Blockchain will diverge into two networks sharing the same history of transactions until the fork date/time.
The most popular example of a fork occurred when Bitcoin Cash broke off from Bitcoin on August 1, 2017 and again on October 25, 2017 when Bitcoin Gold also split away from Bitcoin. The reason for these forks had to do with a difference of vision within the organization.
There are two ways to achieve forks: 1. Miner Activated: miners vote for changes on the blockchain. 2. User Activated: users vote to change the active nodes on the blockchain.
There are likely to be more forks on the bitcoin blockchain because it is the most valued cryptocurrency and there is no defined organization.