My document began to type in brown color with strikethroughs. There is a vertical black line in the margin by all of the brown lines of type. The text will not delete with delete or backspace. If I backspace into the black type, it will turn to brown also.
You are in “track changes” mode, that’s intended for edit-review workflow. It is controlled either using dedicated toolbar of the same name, or by Edit->Track Changes submenu.