Ripple - XRP is a special crypto currency that has built-in rules on minimum balance held in XRP wallet. In order to send from your Ripple wallet you have to hold more than 20 XRP in it.

20 XRP minimum cannot be moved out.

A destination tag is a unique 9-digit figure that can be used additionally to recipients wallet address. It is usually REQUIRED when sending funds to crypto exchanges or anyone else that explicitly asks you to use it (exchange will provide you with information) to identify the receiver in a Ripple transaction. It is not required when you send XRP funds to your BC Vault XRP wallet.