How can i avoid people cross out or edit some parts of a document?

[Marceloconocelo]

Hi, ive made form for my company, and i realized that when i open this PDF (or any PDF) and if i mark a phrase and press delete it will cross out that phrase: 

Is there any way i can "block" people from doing this kind of things to this document? I just want that the people who recieve this form, could only fill the form gaps, but make sure that they can't edit the text of the form or even cross out it. 

[try67]

You can apply a security policy that allows filling in form fields but not adding comments (which is what this strike-through that you see is), via File - Properties - Security. This is not bullet-proof, though. In fact, many applications will not enforce this policy, so take it with a grain of salt.