How much formula dose you 2 month old get and how often do they eat? also do they eat it all at one…

How much formula dose you 2 month old get and how often do they eat? also do they eat it all at one time or within a lotted amount of time? I currently feed her whenever she wants and it seems to be 2 oz we ever 1 1/2 to 2 hours and if I n make a 4 oz she takes about 45 min to eat it with a break inbetween. so I'm not wanting to really put her on a tight schedual but to maybe do more oz and more time inbetwwen. Any suggestions.