Can I make the form un-editable for the approver?

Can I make the form un-editable for the approver, such that the approver cannot edit anything that the requester entered.

The only field that the approver can edit is the 'hidden' fields to requester i.e the 'Approval Status' and signature.

Unfortunately, it isn't possible as you are the admin of the account. However, you are able to hide the approval and signature fields. You are also able to edit these hidden fields on the submissions panel. 

1- Edit your form and add fields whichever you want. Then right-click on the field which you want to hide and select the "Hide" feature. 

2- Please go to the "View Submissions" panel: How to View Form Submissions

3- Edit your submissions panel settings and disable the "Auto Hide Empty Fields" feature and click on the "Edit" button on the right side.

4- Edit the fields you want to edit and click on the "Submit" button.

5- If you do not want to notify the sender of this arrangement, please be sure that you have disabled the "Send on Edit" feature of "Auto-Responder".

Thanks That worked for me.

Is there a way to have the 'Approval' button sent to the approver's email - such that:

1. Requester submits the request

2. Reviewer receives an email

3. In the same email, approver can view details either from the body of the email or attachment (I know how to do this)

4. And then, directly from the email, hit the 'approved' button and approve the request.

Unfortunately no, you need to click the edit submission link manually and click the Submit Approval button to apply the changes.