How to show the header text in 2 lines?

I want 'Pre-Arrival Form' to appear on the second line rather than have 'Pre-' and 'arrival' split over the two lines

Unfortunately, it is not possible with the header field. As a workaround - you can add that text in the Sub Header field and match the style with the Header using CSS.

Here is the CSS code:

.form-subHeader{

  color: #fff4f4 !important;

    font-weight: 700;

    font-size: 30px;

}

Here is the guide: How-to-Inject-Custom-CSS-Codes