Facebook Business Pages have a handy, customizable button that will help visitors to your Page easily complete an action that you specify. Here's how to add an action button:
1. Head to your Facebook Business Page and click + Add a Button to the right under your cover photo.
Something to note: if you don't see the 'add a button' under the cover photo it may be due to you already having one. If you want to change it you still can. Hover over the button and you'll get the menu with the option to change it. Example below
2. A window will pop up with a number of different categories of buttons. Click the little downward arrow to reveal the various available buttons under each category.
Select the button that best fits your page and the action you want visitors to take. Then click Next.
3. For this example, let's say you want to use the "Contact Us" button. In Step 2, Facebook will ask where you want to take people who click on the button. Click Website Link to customize the re-direct URL. (Different buttons may ask for different information.)
4. A little window will pop up and allow you to paste your desired URL. Once you've got it in there, click Save and you're done!
To edit an action button that you've already created, simply hover you mouse over the button and select Edit Button in the dropdown menu that appears.