if you are talking about how some writing programs have a feature where when you make a mistake you can tell it to strike through (put a line through the sentence with the mistake in it....there is an edit button that appears after you have posted. its down with the thanks and hugs buttons. but it only stays there for a short time.

you can also pm a moderator and tell them the edit you want to make or report your post (icon to the left of the post looks like a triangle on my computer and laptop) and then write in the space provided the edit you want to make to your post.

then the moderators will make that edit for you.