You will now be presented with your unique Ethereum address for Binance. This is what you are going to need to enter into GDAX to learn How to send bitcoin from Gdax to binance. Click on the Copy Address button, which will copy it to your clipboard. Now that you have your Binance deposit address, you now need to log back into your GDAX account. It is probably best to do this in a new tab.
At the top of the screen, click on My Wallets. Select the cryptocurrency that you want to withdraw, along with the amount. You now need to Paste the Binance wallet address you have copied on your clipboard into the senders' address box. Finally, to complete your transfer from GDAX to Binance, click on Send.