1993 320i 2l M50 engine.
Haynes service manual 3210 says only BMW dealer can replace Automatic transmission fluid!

3 series right? looking to fill it up? if so there should be a p/s res right at the front of the egine bay thats where you put the atf, looking to change it? i would recommend changing the filter to just drop the tranny pan

If your 320I is anything like my 92 325I the fluid needs to filled from underneath on the trans pan you'll see 2 plugs. One is for filling the other for draining.