I want to play Street Fighter Alpha 3 and Street Fighter 3:Third Strike online.
Indeed, Globe already hit one of the simplest methods.
Depending on your particular emulator (I think Fightcade and some of the others use FBA - Final Burn Alpha?) and particular games supported, many emulators can offer online play in one form or another. For the titles you mention, I believe both of them are compatible with (and using proper emus) GGPO netcode which will mean smooth online play.
Good luck!
I haven’t played the latest Fightcade but the last time I played it, 3rdS never ran smooth, not even offline. Everything CPS1-2 and Neo play great though. Love Fightcade, spent a lot of time playing Turf Masters and ST, my 2 favorite games.