how to prevent other people convert pdf files to other formats

Please can anybody show me how to prevent other people convert pdf files to other formats? Such as Word, Excel, PowerPoint and so on.

Most of the time, when I was providing identity document as pdf format to organization, i would add watermark to it, such as " This [Name of the Documents] is dedicated for authenticating my identity in [organization]; I do not give My permission for any other use and also can not be copied "  ......... in this case, does pdf have any features to delete its content within a period of time (such as 7 days, 15 days or 30 days. Can not be over 30 days)? Since I do not want organization to keep my Identity document forever, even if they promised to be deleted, I still do not trust them.