Change language on newsletter and contact form

I have a site in Spanish and I would like to change the 'first name' and 'last name texts' in the contact form and newsletter in the home page, https://www.stejar.store/contacto

I have tried from another thread:

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.0/jquery.min.js"></script>
<script>
$(document).ready(function() {
	$('.first-name input').attr('placeholder','first new text');
  $('.email input').attr('placeholder','new email address');
});
</script>

However it's not working, not sure what to put

Can someone please help me?

Try this solution with Custom CSS: 

Thank you! I just need to change it in the newsletter form 🙂

On 11/29/2022 at 11:51 PM, KbSass said:

Thank you! I just need to change it in the newsletter form 🙂

Did you solve or still need help?