turbotax

There isn't an internal slot on 2012 or newer iMacs. Use an external drive, or download the software from the web.

(191199)

You will need to buy an external DVD drive. I would recommend contacting www.macsales.com (their phone number is on their site page) and speak to a sales rep and they will help you find one that best suits your needs. Apple makes an external SuperDrive but most experienced users prefer the third party ones.

You buy an external USB optical drive.

Alternatively if you have another older Mac with an optical drive you can setup disk sharing. https://support.apple.com/en-us/HT203973 (Its worth a try if you have an older Mac, but since the article is archived that may indicate this feature is no longer supported)