If you often save documents in pdf and you need at least basic protection of a pdf file from copying, then a proven and preferably as easy-to-use program for working with PDF will definitely not hurt. The most common and accessible to everyone way to protect electronic documents from unauthorized access is to set a password for the document or archive. This is usually done by the built-in tools of the program, for example, in the Acrobat application you can restrict editing, copying content and printing (link to instructions). But you need to consider the following - the file itself can be copied, and if you upload a document and password protected in this way on the Internet, then everyone can easily open it.
Microsoft Office allows you to encrypt your documents and PDf files, which gives you the ability to protect your document with a password. In other words, if you set a password on a document, then no one will open it without it. In document protection, you can set a password to edit the document. That is, a person without a password will be able to view documents, but not edit. This type of protection can be easily compromised and removed. Therefore, if you set a password, then it is desirable for the entire document. Some free PDF editors also have the ability to password protect PDFs, but we recommend using one of the tools below. Of the few PDF editors that also support encryption, not many will do this without adding a watermark to the file, which is certainly not ideal.