I'd personally say how the accounts are stored will depend on the customer implementation, allow me to get Wallet-cli for example. I'd personally also propose you utilize wallet-cli to generate new accounts. There are two ways of creating a vanity BTC address: manually and employing specialized vanity address generator solutions. https://vanity-address-generator30740.frewwebs.com/32398965/5-essential-elements-for-vanity-address-generation