Hard forks can occur in any cryptocurrency network because public blockchains, regardless of how they are constructed, operate in the same way - transactions are bundled into blocks, which are validated only when all validators in a network reach consensus on it.
Validators can propose changes to specific areas of the protocol because they understand the rules of cryptocurrency networks. However, before any change is implemented, all validators must agree on the update. If everyone agrees, developers update the network protocol to reflect the change.
The fork creates a spit in the blockchain, requiring all validators to upgrade their software in order to run the updated protocol. Nodes running the old chain will eventually realise it is obsolete and will migrate to the new chain.

A hard fork is a major change to a blockchain that creates a permanent split in the network. It happens when new rules are introduced that are not compatible with the old version, requiring users to upgrade their software. If some participants continue using the old rules, two separate blockchains emerge, each with its own history. A well-known example is Bitcoin splitting into Bitcoin Cash. Hard forks are often used to add features, improve security, or resolve disagreements within the community. After the split, users usually receive coins on both chains. The long-term success of each network depends on factors like user adoption, developer support, and overall trust.