XRP (Web and Mobile App previous to 4.0 version)
What is the Destination Tag and How do I use it?
Destination Tags are a feature of XRP Ledger payments and are used to indicate the beneficiary or destination for a payment. The destination tag is used to indicate which customer should be credited for that payment.
Think of the destination tag like a unique memo specific to your XRP ledger address. The destination tag is required when sending any XRP from an external address to your Uphold wallet if the transaction does not have a destination tag, or the destination tag is incorrect it will be rejected by our system.
Here is a quick how-to for destination tags: