HubSpot CMS Guide: How to add a form to your website pages
For the most part, you will be creating landing pages when you want to create a page that includes a form. But sometimes, you'll want to add a form to a website page that already exists. Here's how to do so.
1. Add a new module to your website page
Click the Add Module button above the space in which you would like to add a form.
2. Add the form
Select Form from the list of module types.
Then name your form, select an existing form from the dropdown (if you've already created this form for another page on your site), and click Save.
3. Edit your form
If you need to make any edits to the form, click Edit Form and make any necessary changes within the form builder.
For detailed instructions on how to edit your form, read the How to Create a Form section of the How to Create a Landing Page in HubSpot tutorial.