login box

you can use a plugin called Theme My Login
https://wordpress.org/plugins/theme-my-login/

This will allow the login and log out to be part of your site with just a simple menu item.

You can have it so if the member in NOT logged in, all that will show is the Log in ( or you can call it Sign In or anything you like) menu.
and then when they are logged in, all that will show is the Log Out menu.

Hope this helps.