If a text dropdown doesn't have the values you need, you can easily change them. For example, let's say you'd like to enter Ford as an Account and set the Industry attribute to Automotive. Initially, that option isn't available
You can add it by clicking Cancel, then the Gear icon and Configure Attributes
Find the Industry attribute and click Edit
You can modify the list here by creating one option per line
When you're done, click Modify and then Close. Now click New Account and see the Automotive option available.