I think you'd be hard pressed to find any group's bylaws that say the president's job is to "do as she wishes.'' Perhaps she's not really feeling confident and is therefore acting defensive. So, maybe reach out to her, suggest a get together where everyone can review the procedures, make sure all the jobs are getting done. It's a very typical thing, as mum24kids points out, that there would be two sets of eyes on any documents that are going out to the community.
I would enlist the principal's help. She has the right to determine what is distributed in her school, and I would think she would be mortified to have fliers going out with spelling errors and misinformation. Things like that tend to create extra work for the office staff, too. At my school, nothing is supposed to go out without the principal signing off on it. She sometimes delegates that to an assistant principal, but there's always a second set of eyes on everything that goes out. It doesn't take long for her to turn stuff around, and she almost never changes anything, but if there is a typo or something, she will point it out.
We have a new PTA board and I am VP. It seemed that everything was going to run smoothly until the president started issuing things to parents and teachers without the rest of the Board's knowledge with spelling errors, misinformation and things that caused anger from those receiving it. We brought these things to her attention but she insists that as president she can do as she wishes. How do I deal with this? I don't want to be represented by the things she is doing but she is unwilling to change at all.