I add one Campaign.
How to add form data (first name, last name, date, place etc.) in campaign using rest api.
There’s really not enough information here to answer…where is the form? On wordpress, another website, an IS form? If the latter then it will get added automatically. If not, then it would be easier for you to embed an IS form in your outside form and use that so it will still happen automatically.
If you absolutely have to use an outside form then you have a lot of options depending on what you’re using for the form.