Hi Nico,
You can write your Html code in the body of the email template. And in the a tag you can pass tokens in runtime. You can Configure tokens in Email Template Configuration.
Example html code : <a href="{%URL%}">Click here</a>
For your Reference:
Now you have to add the tokens/Placeholders in the email template configuration.
Hope it Helps!!
There is a better way to do it.
Configure a container on your page, within this container you can place multiple texts ( be sure to set render mode to text) and a link button.
When rendered, the elements will be aligned next to each other.
In Studio Pro:
result in Design mode: