Digitvisions is actually incorrect, Rigify comes with IK on the legs and its the active mode by default. You can actually switch between FK and IK.
Looks to me like your almost there. Rigify can be pretty overwhelming, especially if you don’t know the basics of rigging yet but there is only one way to learn and your doing it.
Rigify tries to “guess” the bending direction of the knees based on your meta rig. This means you should have a slight bend in the knees in your meta rig, rigify will take this as a hint so to speak.
The problem is however that even if you do this (you had not done it) it still won’t be perfect. I only recently learned this but Rigify gets confused when the legs are not vertical. You have a nice powerstance with the feet a little apart and this looks great but Rigify will always guess the direction of the knees wrong (too far outward) EVEN when you put a little initial bend in there.
So your only option is to change the stance where the feet are closer together and the legs as vertical as possible.
Here is a screenshot to show you what I mean with the initial bend. It does not need to be much but it needs to be there:
After doing these two things your generated rig should perform much nicer:
The arrow I circled is the Control that you can use to adjust the orientation of the knee. This is something you will still need to do as you start posing your character but the default is much more sensible now.
Rigify is a very nice rig but the controls can be overwhelming if you do not have experience yet with rigging or animating. You really don’t need to use all of them (especially not in the beginning) but I do suggest to look for some video’s on youtube so you have a bit of an idea what they are for and or do.
Or just go and experiment, thats fun too!
Here is your file with some changes if you want to see it in blender. I did not bother with clothes or anything, just did the basics to make it work: