Contract address is an address in the blockchain database where a particular smart contract is stored. Just like with the regular database, you will need to know a contract address to quickly locate it, update its state, or request a particular data.
While keeping the identities and agreement details anonymous, the blockchain allows the users to see the general information of the document. Such information includes the sender's and receiver's wallet addresses*, or the number of tokens kept by the contract, along with its transaction history and gas fees**.
Though to receive such data a blockchain search engine, a.i. a blockchain explorer is used. It finds the contract from the blockchain records by the contract address.
Good to know
*Cryptocurrency wallet is an app (web, desktop, mobile) or a physical device that stores your public and private keys. Metamask, Coinbase Wallet, and Trustwallet are among the most used crypto wallets. Each wallet has its unique ID known as a wallet address.