I would like to delete my account on MSE, but I dont know how to do it. Could anybody help me in this matter. Thank you in advance
The help center contains a page with instructions for how to do it.
Since you have significant contributions to the site, you contact Stack Exchange and request the deletion of your account. You will be told what further actions you need to perform to ascertain that it's really your intention to have your account deleted, and when those are done, your account will be scheduled for deletion. The process may take a couple of days.
But please think carefully whether you really want to delete your account before doing anything rash.