Let’s see how the pattern of this crop top is drafted.
It’s done in a shirt fabric, so any lightweight cotton as popeline will work. You can also use something a bit stiffer as taffeta if you want the sleeve to hold the volume a bit more.
Start from a basic block with darts, matching sleeve and appropriate ease allowance for the fabric you will be cutting.
Get the front. Cut through the waist dart, close the shoulder one and open the volume all at the waist.
Redraw the apex of the dart 2cm below bust point.
On both front and back draw the straight neckline 6-8cm above the armpit, perpendicular to the center.
Draw also the raglan lines: the front one starts from the high point shoulder, the back one starts from the center of the neckline.