In ‘ERC20’, ERC stands for Ethereum Request For Comments and 20 stands for a unique ID number to distinguish this standard from others.
One of the most significant Ethereum tokens is known as ERC-20. ERC-20 has emerged as the technical standard; it is used for all smart contracts on the Ethereum blockchain for token implementation and provides a list of rules that all Ethereum-based tokens must follow.
ERC-20 is similar, in some respects, to bitcoin, Litecoin, and any other cryptocurrency; ERC-20 tokens are blockchain-based assets that have value and can be sent and received. The primary difference is that instead of running on their own blockchain, ERC-20 tokens are issued on the Ethereum network.
ERC-20 Token Standard:
Some other ERC may will replace ERC20:
EIP-721: ERC-721 Non-Fungible Token Standard
EIP-1155: ERC-1155 Multi Token Standard
EIP-1337: Subscriptions on the blockchain
What is EIPs:
EIP stands for Ethereum Improvement Proposal. An EIP is a design document providing information to the Ethereum community, or describing a new feature for Ethereum or its processes or environment. The EIP should provide a concise technical specification of the feature and a rationale for the feature. The EIP author is responsible for building consensus within the community and documenting dissenting opinions.