Need Help With existing PDF guide that is currently editable on the 1st page

We have a PDF guide that was created for us that is 7 pages long. We are providing this guide to multiple users in our office. On the lLOWER LEFT front of the guide we have an "editable " area where the user can place their personal contact information on the front of the guide and then send the guide to clients. (SEE ATTACHMENT) HERE IS THE PROBLEM WE ARE HAVING- The user fills in their personal information on page 1 of the guide and then "saves" it to somewhere on their desktop so they can then email the guide to clients. But whats happening is that when the user emails the guide they edited to clients, the client will then open up the PDF guide and then see that the area that the user filled in their personal information is still highlighted and still "FILLABLE" which is not waht we want. We need a PDF expert to provide a solution where once the user fills in their personal information on page 1 and Saves it then this fillable area will "lock" and no longer be editable. That way when they send it to clients, their personal information on page 1 will be "locked in" and will no longer be editable. That way when the client open up the PDF that was sent to them from the user, they will not be able to see that this page 1 area is no longer editable. Can you program the PDF guide for this or explain how the page 1 fillable area once it is filled in with information that it can be "locked in" by the user so they can then email it to clients? NO GENERIC RESPONSES- Explain how you can help and we will hire you :)