Hi @Katrina_Boyd - if you are using the embed code you should have something like this:
<iframe
class="airtable-embed"
src="https://airtable.com/embed/shrj40LATHogtA?backgroundColor=yellow"
frameborder="0"
onmousewheel=""
width="100%"
height="533"
style="background: transparent; border: 1px solid #ccc;"
></iframe>
You can increase the height number to extend the length of your form. Might take a few goes to get it right - not too short, not too long.