How to make the Invoice header un-editable for few users?

Summary:

We want to restrict few users' access such that they are unable to make changes to invoice headers. These users should only be able to add invoice lines but should not be able to edit the header. Is this achievable by restricting privileges or DSPs or will it have to be page customization?

Content (required):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):