Can PHP code be used without permission? I am using PHP code to make a website. Can anybody can use my PHP code without my permission because of open source?
PHP is open source, anyone can use it. Your code in PHP is your copyright, you decide who can use it. This is just like: English is open source, anyone can use it. Your novel in English is your copyright, you decide who can use it.
You seem to assume that copyrights require paperwork such as registration. This is wrong, copyright is automatic. And it prevents the downloader from making the sort of change that you suggest. In fact, it prevents the downloader from using your template at all. The only reason the downloader can use that template is because you've granted him a specific license to ignore some copyright rules, but the default remains. And you did not grant the right to alter the template to free users.
It is highly unlikely that any such program would be protected, insofar as there is minimal expressive creativity involved in the code – for a standard &quot;hello world&quot; program. For instance, the following REXX code is not creative: say 'Hello world' The language itself determines that the relevant statement is &quot;say&quot;, and I did not create the text, somebody else did and I just copied it. A version that goes outtext = 'Hello world'; say outtext is not creative either (this approach to typing text is implicit in &quot;programming&quot;, and the variable name is a patently obvious choice. It would be possible to write code that is very creative, but which only types &quot;hello world&quot;. So it depends on the code.
Yes, you could do this be means of the EULA, provided you are not in the EU yourself. You only have to comply with the GDPR if you are offering a product or service to people that are in the EU. If you are making it clear that whatever you offer is not available to Europeans, you make your site exempt from the GDPR.
Yes, commercial use is allowed for the AGPLv3 license. You can charge for your use of the software so long as you provide a way for the public to download the source code in its entirety.
There are a number of existing legal sites that do this, for free or for pay. The main concern for a website operator pertains to the DMCA "safe harbor" provisions, which protect against vicarious liability for infringement. A "report piracy" option is not sufficient; see this answer to a related question.
Exactly the same way it works over all other content There are no special classes of copyright, there’s just copyright. What a user of a service may do with copyright materials will be spelled out in the licence. If there is no licence, then they are left with fair use/fair dealing.
No, it means you can't copy it. By default, the copyright to a work is owned by its creator, and nobody else is allowed to copy it, or create derived works, without their permission. That permission can be granted by a license. "License unknown" doesn't really tell us anything, but it certainly isn't clearly granting you permission. So you don't have permission to copy, and thus you cannot. You would have to seek permission from the copyright holder. See also If no licence is distributed with an application/source code, what license applies by default if any? (Some jurisdictions do allow for "fair use" exceptions, which allow you to copy a work without permission. You haven't said what jurisdiction you are in.)