Do we need to change our web pages?

The short answer is no. That's the beauty of search engine advertising.

But just because you don't have to doesn't mean you shouldn't.

You may want to make a new landing page for a major product or service and test variations of your pages to improve your sales conversion rate.

In order to track your ads and actions (highly recommended) you will need to add a few lines of code to some of your pages.