如何使用POST方法？

I read about GET and POST on the internet and I am quite confused about it. I understand most of it but, I have few confusion like Should I use GET method to get (retrieve) the data from action page, we cannot change server data sing it (edit, delete, update) while post is used to just post the data on the server and we can do (edit, delete, update) with this. Like I have following example I am confused on how to make it using POST method? And I have no parameter to pass in the url. I also see, I cannot make it asynchronous. on the internet and I