Hi Elly,
Due to Dynamics Marketing has its own back-end program to process submitted data from marketing form,(I thought it's should be same for Hubspot)
currently we could only build native marketing form with Dynamics Marketing integrated designer.
But you can embed Hubspot forms on a web page(e.g: on Portal) and let Dynamics Marketing scan these fields and map them to contact's corresponding fields by adding some necessary attributes to these fields.
"In a word, we couldn't convert other forms as Dynamics Marketing native form;
but we can use Form Capture feature to make forms from other platform work."
https://docs.microsoft.com/en-us/dynamics365/marketing/embed-forms#use-form-capture-to-integrate-a-form-created-externally
In addition, if your Hubspot form was just consisted of some text fields(e.g firstname, emailaddress, comment), checkbox or single-option drop-down list,
then the feature would work well;
if your form had some complex data to submit, then you might need to create a same native marketing form again manually.
Comparison between native form and captured form:
https://docs.microsoft.com/en-us/dynamics365/marketing/embed-forms
Regards,
Clofly
