Hi @DavidCrompton,
The share.hsforms.com links are direct links to your form. You could also consider them preview links.
They work great for testing but generally, it’s not considered best practice to use these standalone. Rather, you would place them on a HubSpot page (Menu > Marketing > Website > Landing Pages) or embed them on a non-HubSpot page. On a page, visitors will see your company branding and you can provide more context as to what they’re signing up for.
Hope this helps!