hi there! if you would have taken at least 5 - 10 minutes to search, other users have asked the same question as you.
for example, but not entirely:
"Best SNES emu for N3DS?",
"GB, GBC, GBA, NES, SNES etc. Emulators for O3ds and ONLY for Old 3DS",
"Best SNES emulator for new 3DS?", and
"Best SNES emulator for CFW N3DS?".
in my opinion, for old 3ds, use libretro pocketsnes or
snes9x. for new 3ds, use libretro catsfc (or just
custom virtual console). libretro can be found
here. you have to use a certain stable version there to not see some screen tearing though.
this topic can be closed now.
dotarice