login problems, maybe?

I gave her a wordpress name and password, but when she tried to login it sent her to my site as a 404 error page. She said she changed it when she clicked the “change password” at the bottom, but kept the password the same and wordpress let her (which I thought was weird). After that when she would login with the new.old password it would bring her to my site, but not under wordpress. There was nothing saying she was logged into wordpress at all. 

In fact if you click on “visit site” at the top of the wordpress page it takes you to the site, but nothing at the top saying wordpress or to click back to the wordpress section for the website.

I am not sure what is going on here.