Help Please. When I create a document in Pages and try to convert it to PDF my AVG Virus checker kicks in and quarantines it. PDF:URLMalinf[TRJ]. What do I need to do?

Uninstall AVG. No Anti-Virus software or so-called “cleaning” apps are needed or recommended for Mac OS. They can conflict with Mac's own built-in security. At best they will slow your Mac by using unnecessary resources and at worst will bork your entire system.

Follow macjack's advice. There have been hundreds of posts over the last year or two that can be traced to anti-virus products installed on Macs disrupting normal operating system and application functionality.

As there are no known viruses on Macs, you would however, be better served by downloading and installing Malwarebytes, which is a purpose-built anti-malware tool that we regularly recommend. It does not interfere with the operating system, or applications. If it finds malware, it will offer to remove it.

I have no affiliation, derive no compensation, or receive any benefits from recommending Malwarebytes.

How are you trying to convert it? Are you using the built-in functionality - either File -> Export To -> PDF in Pages, or via the print dialog's ability to save to PDF? If so, that's definitely a false detection by AVG.

On the other hand, if you're using some unnecessary third-party tool to do the conversion, it may not be a false positive. If this is the case, what tool are you using?