can you play this on PC if so how can you download it

If you own PS3/PS4/PSVita, just go and buy the game from PS Store. The old f/f2 for PS3/PSVita are not that expensive (about $20-30 when I last checked). The newer Future Tone/X are more expensive but with more up-to-date contents and/or better graphics.

If you only have a PC and don't want to get a console, there are still simulators for Project Diva series on PC (namely the old Chinese Project Diva PC, which simulates the original PSP Project Diva, and PPD (https://projectdxxx.me) which simulates the arcade version/Future Tone)

I would not recommend running the PSP/3/4/Vita games on emulators, because firstly you need to have a real console to legally obtain the ROM (not really true for PS3 but AFAIK you still need a specific BD drive to dump the discs), and secondly emulators cause delays (more or less) and that could be awful on rhythm games.