Button.
Buttons are used to trigger an action or event, such as submitting a form, opening a dialog, or sending a mail ie., Call to action.
And has different sizes and states.
Basic Buttons
These are basic rectangular solid buttons which you can find across various websites.
Outline Buttons
These are modified yet same as Basic buttons, just added with a colored border for a different style.
Link Buttons
The link button has anchor tag which enables link action by adding links to href tag.
Buttons with icon
These buttons have icon which enhance the overall experience.
Floating action buttons
Trendy floating buttons which usually hover over screens across various apps.