Address is an account attribute derived from the public key. The address also contains the chain ID that identifies the blockchain network, therefore the address on the Mainnet cannot be used on the Testnet and vice versa.
Normally, the address starting with
3Prefers to the Mainnet, and the address starting with
3Nrefers to Testnet or Stagenet.
The address is used to obtain information about the account:
See examples in the How to Retrieve Information from the Blockchain article.
The address is indicated: