if your talking about going from your mixer to your pc you'll preferably need record out on your mixer/amp/equaliser. not all mixers have this.
if your going to a laptop(also alot of pc's) you'll also need a phono to 3.5mm jack cable . in some cases you'll need an unearthed extention with a laptop to stop the buzzing sound, unless, your battery lasts the duration of whatever you doing.
and if its pc/laptop to mixer....visa versa but to your line in.