If a submit button doesn’t appear at the end of a form, it usually means that there are some required fields that are unanswered, and that the ‘questions to go’ counter is active on your form. Required fields are marked with an * when completing a form.
If the user tries to click on the 'X questions to go at the bottom of the form…
…then they will be sent to the first question they’ve missed and it will be underlined in red.
You might like to remove the ‘questions to go counter’ as this will show the submit button immediately. You can do this by going to Theme > UI Elements > Submit button in the form editor, and turning off the ‘questions to go’ toggle.
If you turn it off, you will see the submit button immediately on the form. If the user tries to click ‘submit’ before answering all required fields, they will again be sent to the first question they’ve missed and it will be underlined in red.
If you have the ‘questions to go’ counter on, then the submitter will see this until all required fields are answered.