After a user submits a form, they can be redirected to an external URL. You can add a redirect if you are on a paid plan in the Settings > Emails & Actions tab. Click to add a new Submission Message and select "Redirect to a custom URL".
Then, paste in the URL you'd like to redirect to. This can to another Formstack form or an external site. To pass submitted form data through the URL, check the "Append Submitted Data to URL" option under the URL. If you are redirecting to a Formstack form, all of the fields with the same field names as contained in the first form will be pre-populated with the previously submitted data when the user is redirected to that second form.
For example, if the redirect URL is:
And the submitted data is appended to the URL, the final URL might look something like this if the form consists of fields labeled "Address":
Note: Internet Explorer limits URL size to around 2,000 characters, so if you get an error in IE, but not Firefox when appending all the data on your form, you are probably over that character limit. In that case, you would want to create a custom redirect URL passing on only the needed fields instead of all the fields. It would look something this:
Click here to learn more about pre-populating form fields!