The Sit and Reach test measures lower body flexibility. Specifically it is measuring hamstring and lower back flexibility. The assessment will be taking sitting up on the ground with your legs straight out in front of you and feet flat against the measuring box. Shoes will be off.
There are many variations on how to stretch your hamstrings and lower back. The most important thing to remember if you want to become more flexibility is consistency. Also remember to do a short 5 minute warm-up before stretching for a long time, such as jumping jacks or jogging in place.
Here are some stretches to do at home that you should hold for 20-30 seconds for the most effective results and should be done 4-5 times a week or more.
The goal is to reach your toes, preferable further.