Hi @Richard_Foxworthy - this is probably something to do with the webpage itself (structure/styling) rather than the Airtable form. The form embed code is:
<iframe class="airtable-embed" src="https://airtable.com/embed/[form id here]?backgroundColor=green" frameborder="0" onmousewheel="" width="100%" height="533" style="background: transparent; border: 1px solid #ccc;"></iframe>
This has 100% width, so will fill the page “container” it is embedded into. It will almost certainly be a problem with the container - too narrow, too much padding or something like that.
A simple HTML page will show you what it should look like:
<html lang="en" dir="ltr">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://static.airtable.com/js/embed/embed_snippet_v1.js"></script><iframe class="airtable-embed airtable-dynamic-height" src="https://airtable.com/embed/[ADD YOUR FORM ID HERE]?backgroundColor=green" frameborder="0" onmousewheel="" width="100%" height="706" style="background: transparent; border: 1px solid #ccc;"></iframe>
Copy the above snippet, paste it into a text file named index.html, change the form ID to be your form ID, then open it in a browser and you will see what I mean. Resize the browser to get a mobile view (or use Chrome Dev Tools if you are familiar with that).
I would recommend using the autosize height feature of the embed code too:
Hope this helps!