The question of opening the .fp3 and .fpx files sometimes puzzles the end users. The formats are very popular and there should be some convenient tool for opening, viewing and printing it. And there is!
FastReport Viewer is a free tool for working with .fp3 and .fpx files. Now it supports all modern FastReport formats. And not only that: it automatically "recognizes" the version of .fp3 between VCL and FMX.
It's free, and it works under both Windows and OSX.
Check it out here https://www.fast-report.com/en/product/fast-report-viewer/