The option to "Add DT" will appear when the destination Ripple wallet address has been entered.
When sending funds via the Ripple network:
Enter the Ripple address
click "Add DT" button that appears above your entered address
What is a Destination tag?
Destination tag is a 9-digit figure, unique to each hosted wallet. It works as a wallet address.
Destination tag is not required when sending funds to your GateHub Ripple wallet.
If you are sending to a GateHub hosted wallet, a Destination tag is required.
Some services require a Destination tag to be specified in addition to the destination wallet address in order to credit the correct account.
If you have sent funds without a Destination tag when it was required, please contact the receiving party to recover your funds. All cryptocurrency transactions are irreversible and GateHub will not refund such transactions.
Where do I find the destination tag?
The destination tag for your wallet on another service can be found by going to that account.
Find the option to deposit XRP.
There are two possibilities:
There will be a Ripple address displayed and a 9-digit number displayed separately.
There will be a Ripple wallet address that has ?dt="9-digit number" added at the end. You will need to copy the address and destination tag separately without "?dt=".