JSFiddle - React, Tailwind, and code Playground

HTML

<textarea name="your-message" cols="40" rows="10" class="wpcf7-form-control wpcf7-textarea" id="ass" aria-invalid="false"></textarea><br>

tak jest:
<button id="b1">first</button>
<button id="b2">second</button>
<button id="b3">first</button>
<br><br>

a tak bym chciał:  

<button id="c1">NAZWA-BUTTONA</button>
<button id="c1">NAZWA-BUTTONA2</button>
<button id="c1">NAZWA-BUTTONA3</button>

JavaScript

b1.addEventListener('click', function() {
  ass.value += 'fass, ';
});
b2.addEventListener('click', function() {
  ass.value += 'asf, ';
});
b3.addEventListener('click', function() {
  ass.value += 'fdsfdss, ';
});

//* tak bym chcia: *//

c1.addEventListener('click', function() {
  ass.value += 'AUTOMATE FROM: NAZWA-BUTTONA';
});