I really need feedback tom improve my writing skill a lot.
No, you don't. I can hardly find any errors!
Kathy did a great job, but even some of these comments are not actually necessary. For example:
There are three reasons why I think an elephant is the most popular in Thailand. (you can omit this sentence-readers can count how many reasons
This is a great idea for some situations, because it is never god to use more words and sentences than necessary. But in this case, it helps to tell the reader that you have 3 reasons, and then the reader will be able to organize her thoughts while reading.
Really, you have almost perfect English.
But why did you separate the first sentence from the rest of the paragraph? Do it the way you did in paragraph 2, where the first sentence is part of the paragraph:
First, in the past, King Phumiphon always rode an elephant not only for battle but for sightseeing. There were wars between Thai and Burma and a lot of high-ranking soldiers ....Congratulations, Keng. Your hard work has really paid off.And Kathy, thanks!! Without you, a whole week would have gone by before he got help!
One more thing Kathy is right about:
They are capable of bringing...
They are capable to bring...