Hi,
From the information i found here (http://h20564.www2.hp.com/hpsc/doc/public/display?docId=c04551667) i can say yes, you can upgrade the GPU of your computer.
That RX 460 will fit and work without any problems, but i would recommend a Nvidia GTX 1050Ti. 1050ti is under 150$ mark and will give you better performance over RX 460 at more GPU-demanding games.