1) The placement of the word "most" is incorrect. Either move it before the word "enjoy" or after the word "beach". 2) Within a single sentence, you shouldn't switch the subject from first person to second person. 3) use the plural of the word "stress". 4) volley ball is one word. "volleyball" 5) I think the word "exercise" is not needed there. Unless you are specifically talking about exercises other than running. Here is one corrected version: Holiday: beach or mountain? I enjoy the holiday on the beach the most because I enjoy the sun, the sand and the sea. There you can rest and relax from the day to day stresses. You can do many activities like running or playing volleyball. It's a good way to spend a pleasant and relaxing time with friends and family.

It is best if you can ask it in the entry section where we can correct it easily and that you can see what has been changed because of the formatting features found there.

In addition to what Michael said, the first sentence is a little off. If you are speaking about a specific time you went to the beach, you would say "I enjoyed the holiday at the beach the most", but if you are talking generally about whether you like the mountains or the beach better, you should say "I enjoy holidays on/at the beach the most", or "I enjoy beach holidays the most", or "I enjoy vacations at the beach the most". Cheers!