Evenly spaced increase

Evenly spaced stitches means that the number of stitches between increases is approximately the same. Since you are increase 50 sts over 94 current stitches, and 94/50=1.88 you should put (on average) 1.88 sts between increases. That means your increases will be done in some combination of (m1,k1) and (m1,k2) repeats.

There are helpful calculators available online that will tell you how to space your increases based on the current number of stitches and the number of stitches to increase. I found many such calculators by googling "knitting evenly spaced increase calculator." This calculator says to work your increases (50 increases over 94 current stitches) as follows:

K1, (M1, k1) 3 times, (M1, k2) 43 times, (M1, k1) 3 times, M1, k1

If you prefer a kfb increase, you could work your increases this way:

K1, (kfb) 3 times, (kfb, k1) 43 times, (kfb) 4 times

If the pattern doesn't specify what increase stitch to use, it's up to you. Generally with evenly spaced increase you want to use whichever method will be most inconspicuous. M1 is the usual choice. Kfb creates a bar on the front of the work that looks like a purl, so it looks fine on garter stitch but it looks a bit strange on stockinette.