I have sent bitcoins from coinbase to my email address but there on my email I just see an email that I have received BTC from Coinbase. How do I retrieve those bitcoins from my email to transfer them over to another wallet?
When sending Bitcoin from Coinbase.com to an email address, you are sending the Bitcoin to another Coinbase.com account linked to that email address. So for example, if you had a friend who has a Coinbase.com account and you wanted to send them Bitcoin, you could ask them for their Coinbase.com email address and then send the Bitcoin to that email address, where they would claim it on Coinbase.com. Reference
If you simply want to move Bitcoin outside of Coinbase.com to a Bitcoin wallet, you will need to send the Bitcoin to your public address.
Since you already receive the bitcoins in your email all you have to do is click verify. Then You should be lead right back to coin base. Look at the one that says bitcoins and the amount you receive. You would then press The sell button after clicking bitcoin then you would put in the amount you want to receive for instants you could say send from bitcoin to my bank account or credit card you used when signing up for coin base. For example you could put in 0.07. For your bitcoin and it will automatically show you the amount you will receive. Then hit the sell bitcoins button And you will immediately receive a confirmation of when your funds will be available.