Go to the Keyword Planner home screen, choose Tools and Analysis, select "Get search volume for a list of keywords …" and, under "Option 1: Enter Keywords," paste in the list.
When you click the blue Get Search Volume button at the bottom of the screen, you'll get a list of results. By default, Google puts these into "Ad group ideas"; instead, click on the tab labeled "Keyword ideas" to get the full list.
If you don't have a list of keywords, or if you do but aren't sure which ones best describe your business, you can use this same tool to find relevant keywords. Open Tools and Analysis again from the main menu, but this time select "Search for new keyword and ad group ideas." Instead of cutting and pasting a list of terms, put your website address into the box labeled "Your landing page".