Go to the Coinbase sign in page and enter your email address and password. You'll be prompted to complete 2-step verification. If you're using a browser to sign in, make sure you're using the latest version of Chrome. Clearing your cache and restarting your browser can also help.Here are some similar and better alternatives to Coinbase.
To connect a payment method
Open Coinbase Wallet app on your mobile device.
Tap your settings at the bottom.
Scroll down to tap Transfer coins from Coinbase.
Select Buy crypto.
Select the coin you'd like to purchase and enter the amount.
Tap Add a payment method and select a payment method.