The most obvious choice for p65 to jpeg conversion would be to use old Adobe PageMaker to export the old documents (.p65) or at least some of their elements as JPEG pictures (.jpg, .jpeg). If you do not have access to the original tool, you may be at least particularly successful with Adobe InDesign.
Unfortunately, PageMaker files are typically not supported in other programs and quite frankly, we do not know about any 3rd party programs that still support them, except perhaps InDesign.Open P65 file Open JPEG file
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Mac version od Adobe's popular document designing and publishing software