Today I am very glad to have the chance to run for the position of president of the students’ union. I am a student in Class 1, Senior 3. ...
One possible version：
Today I am very glad to have the chance to run for the position of president of the students’ union. I am a student in Class 1, Senior 3.
Since I came to this school, I have been class monitor. I have done a very good job for my classmates, and in turn both my classmates and my teachers give me high praise. I am good at communicating and organizing, and always ready to help others. Moreover, I have a variety of hobbies, such as basketball, football, table tennis. Besides, I’m active and modest, and I love learning as well. I am sure that I am qualified for the position.
If I become the president, I will try my best to make the students’ union attractive by organizing different activities. I will do what I can to meet your needs. I sincerely hope you can give me a chance and I’m sure I will be a good president. Thank you.