Submit form only when certain text is entered

Is there a way to only be able to submit a form if certain text is entered into textbox

Yes, that is possible through a Show/Hide conditional logic

I created a conditional on this form so that when

Textbox labeled COUPON  Contains "JOTFORM"

THEN  Show  Submit

Otherwise the submit button will remain hidden.

You can also choose other options as  "Starts with" "Is Filled" "Is Empty" etc.