How can I add buttons to my Emails?

How can I add buttons to my Emails?

I need to be able to add buttons to my emails fore the reader to choose what to do next.

For example:

Button 1 will result in a new customer journey to be triggered

Button 2 will result in a pop-up appearing to capture some data

Button 3 will be a no thank you selection.

I cannot work out how to implement these.  Please advise.