states are stored on evm and every full node has a copy of the evm. when a transaction happens everyone full node runs this transaction through evm and agrees upon a state.
Nodes store state of EVM
A reusable snippet of code (a program) which a developer publishes into EVM state. Anyone can request that the smart contract code be executed by making a transaction request. Because developers can write arbitrary executable applications into the EVM (games, marketplaces, financial instruments, etc.) by publishing smart contracts, these are often also called dapps, or Decentralized Apps.
pokermaster