A scalloped front is where the lace or skin on a front hair line is cut in a saw-tooth shape—Zigzags.
It broke up the straight front hairline and made it slightly more realistic creating a softer and more natural appearance
We usually don't make scallop to lace material can already create a very natural hairline, meanwhile lace scallop will make the lace edge fray more rapidly. Scallop front usually apply to skin material only.
Here below is the scallop size options for your reference, you can compare the scale under the sketches and order a proper scallop size for yourself.