There are a couple things we frown on around here. One is major edits to a post after there are responses that change the content or meaning, UNLESS, the original part is left intact and the additions are clearly noted. Usually that is done by posting AbE (added by edit) before the new content.
Minor edits to correct spelling or add a missing word, for formatting and such are fine, as long as the added word did not change the meanings. For example if I went back and edited "I do believe in GOD" to "I do not believe in GOD", that should be noted as an edit in the message.