Whenever you have a specific action you want your visitors to take on a page, the Call To Action module is your best available tool. And a very good one too.
Simply, add your call to action pre text on the editor field, set the button text and colors, and you’re done. Depending on where in the page you are using your call to action you may want to have a bigger or a smaller call to action box. You can select the size for this module in its options too.
To learn more about call to action buttons and how to design them, check out this article by Unbounce.
Please note: the modules availability and their specific settings depend on each theme, not all themes include the same modules with the same settings.