Is there a way to lock the form so no one can change the answer?

I have a form where I don't want to anyone from our team to change what a customer submitted because the customer signed it and need to know it can't be tampered with. But there is a "for office use only" where someone from our team needs to complete the form on our end. Is there a way to lock the form so that no one other than the customer can change their answers?

I understand that you want only the user to edit his information. I have checked the both forms in your account and there is no 'For office use only' section available. Could you let us know the form ID that you are working and the workflow how the form works so that we can assist you further?

We will wait for your response. Thank you!