Buttons should be a call-to-action, and link to a webpage where your users can complete that action. You can add an icon to your button to show users the type of action they will be taking.
It is very important to have good link text for your button so users can read where it will take them, whether visually or with screen reading technologies.
You can go to our page on Accessible navigation for more advice and practical resources on creating good link text.
There are 4 different options to customise your buttons, and each will have a different effect on your page.