You can set fields as required on your HubSpot forms so that visitors must fill out the field in order to submit the form. To do so:
- In your HubSpot Marketing Basic, Professional, or Enterprise account, navigate to Contacts > Forms.
- Hover over the field you wish to make required, then click Edit.
- On the left-hand side, scroll down to Make this field required and check the box next to it.
- Click Save at the upper right to save your changes in the form editor, and Publish to take them live on the form.
The field will now appear with a red asterisk next to it. If a visitor does not fill out the field, an alert will appear beneath it when they try to submit the form.