Targeting by URL is the default targeting method, and is required, as mentioned in the article explaining the available targeting options.
Indicate the pattern shared by URLs you wish to target by using one of the three modifiers (corresponds exactly, contains, and regular expression) and/or one of the two available operators (include, exclude).
Use URL Ignoring Parameters when testing a single page,
Use Corresponds exactly only when adding query parameters or hash parameters to the URL significantly changes how the page displays (Ex: if you want to target the test with a specific utm parameter),
Use Contains for experiments if you want to target a subset of pages (Ex: add Contains: /product to target all product page URL’s),
Use Regular expression to target complicated URL structures (Ex: All Product Pages begin with an SKU of 4 letters and 7 numbers) You can create Regular Expressions on Rubular.com.
You can add multiple URL conditions by clicking on the "+" button. The conditions are cumulative (equivalent to an OR operator). If, for example, you wish to target all the pages of your site except product pages, you will use the following conditions:
If you wish to target two specific pages, use the following conditions:
You can add as many conditions as you like.