Tap the menu icon near the top left of the screen to open the Navbar.
Select Buy from the Navbar.
Enter the amount in digital currency (BTC, ETH, etc) or your local currency that you wish to buy.
Select the balance you wish to deposit to.
Select your desired 3D Secure card.
After reviewing your order, select Buy.
Select Verify Now on the confirmation window. You will be redirected to your card issuer's secure portal.
Complete any required steps to authorize the purchase with your card issuer.
You will be redirected back to the Coinbase app and your purchase will be complete!