Press

 <form>
   <input type="text" name="example" id="example" />
 </form>

 import { Target } from '@serenity-js/protractor';
 import { by } from 'protractor';

 class Form {
     static exampleInput = Target.the('example input')
         .located(by.id('example'));
 }

 import { actorCalled } from '@serenity-js/core';
 import { BrowseTheWeb, Press, Value } from '@serenity-js/protractor';
 import { Ensure, equals } from '@serenity-js/assertions';
 import { protractor, Key } from 'protractor';

 actorCalled('Priyanka')
     .whoCan(BrowseTheWeb.using(protractor.browser))
     .attemptsTo(
         Press.the('H', 'i', '!', Key.ENTER).in(Form.exampleInput),
         Ensure.that(Value.of(Form.exampleInput), equals('Hi!')),
     );