After we embed this script, then users access our website, see this form visible (the screenshot below), and then the users fill the information and click submit
But I wonder if there is any hubspot API, which can be used to sent directly to hubspot with a specific hubspot form selected, without showing any form
The goal is, in our website, we show a button called "Contact Us" -> user click this button -> send predefined content to hubspot
Yes, you can use HubSpot's Forms API to submit form data directly to HubSpot without displaying the actual form. You can send a POST request with the predefined content for a specific form by using the form's GUID (which you can find in your form's settings).
This allows you to submit data programmatically when a user clicks your "Contact Us" button, bypassing the need for the form to be visible on the page.