What version of Moodle are you using? If all three editors are available then they should be able by default to choose - for example in 2.9 and 3.0 from the user menu >Preferences>Editor preferences or if they are using an earlier version, from Administration > My Profile settings > Edit profile.
Thanks Mary, really appreciate your help.
With your help above, It must have more to do with users being able to edit their own profile for text editors, as this has been disabled by a previous administration.
I am assuming this is in defining roles for Authen users - if users can edit their profile, will this automatically allow text editing choice?
I do not know a capability for this. Have check your own profile preferences as administrator? Are you able chose each of the editors yourself?
It would be helpful to know your Moodle version. The way the editor is set was changed recently.
Here's what I do. Go to Site Administration | Pluggins | Text Editors. Then sort the list so that your preferred editor is on the top (I like TinyMCE, see my graphic). This becomes the default. Users can still change from this. Mary might be able to correct me if I am wrong.
Jeff - if you want users to be able to edit their own profile then check the authenticated user role has moodle/user:editownprofile set to Allow. Perhaps a previous administrator disabled this.