The seat height can be adjusted according to your size. As for outdoor bicycles, there is some clearance between the pedals and your pelvis in order to ride with ease the most optimal. Your knee should keep an angle of 5 to 10 degrees when you pedal. If you need to extend your foot to reach the pedal, you’re too high. If you feel discomfort that makes you put yourself in the position of dancer when you pedal, you’re too low. Test different heights over a few hundred meters, you’ll quickly fixed.