How to use a First Name only on email or thank you page

How can I populate a thank you using the first name only?

We can use :first and :last parameters within the full name field {tag}.

For example, if your full name is {fullName3}, you can use the next tags:

{fullName3}
{fullName3:first}
{fullName3:last}

There is also a guide about the Address fields:

How to Strip Headers from Postal Addresses in Email Alerts

Thank you.