What is maximum CPC?

Maximum CPC bid: Definition. A bid that you set to determine the highest amount that you’re willing to pay for a click on your ad. If someone clicks your ad, that click won’t cost you more than the maximum cost-per-click bid (or “max. CPC”) that you set.

For More Information Please Refer: https://support.google.com/google-ads/answer/6326?hl=en