At least one of the keywords in your ad group in your headlines

Remember, the headline is the clickable link at the top of your ad.

The description is below the headline, Google will automatically test combinations of headlines and descriptions, so be sure any combination will read well. It's important to include text from keywords, because that's what potential customers are thinking about.

If your ad connects with what they're searching for, they may be more likely to click on it. Also, there are a couple of advanced tools that place the keyword in the headline in certain customizations for automatically tailoring ad Copy.