Option 2: Another account can announce the public key of the new account to the blockchain
Any type of transaction in which the recipient is the new account will do. The sender needs to specify the new account public key as the "recipientPublicKey" parameter for the transaction API or using the wallet "Recipient Public Key" field. Most exchanges which support ARDR or Ardor child chain tokens, already supports this public key announcement function. This procedure is also suitable for companies that want to announce the public keys of their user accounts, hence the blockchain integration in the current business processes is smoother and seamless.