You can find license information for individual icons just above each icon. You can also get more information about the license by clicking the license link itself.
All Premium icons are protected by the same standard Basic License. You can read about it here: https://www.iconfinder.com/licenses/basic. You will have to pay attention to the Free icons, since they can be protected by different licenses.
You can also filter your search by the License Type on the left menu, as in the screenshot below:
For more information about licenses, see our License Overview.