How do I get rid of the red letters when I correct in spellcheck?

[Chamber]

I wrote a letter, then did a spell check. I corrected a few grammatical
errors and afterwards, my whole letter is filled with red lines. What do I
do to get it back to normal?

 

[Jay Freedman]

I wrote a letter, then did a spell check. I corrected a few grammatical
errors and afterwards, my whole letter is filled with red lines. What do I
do to get it back to normal?

It would seem that you have Track Changes turned on. See
http://www.shaunakelly.com/word/trackchanges/HowTrackChangesWorks.html.

Turn off Track Changes, and either accept or reject all the changes
that are in the document.