Members of a wiki-site can have more rights than anonymous or registered users on wikidot. This depends on the setup of the permissions in the Site manager.
There are four ways to join a Wikidot wiki. (Note, if you start a wiki, you are already the admin of that wiki). By application, by password, by being invited, or by using the Join button. Before you can join any wikidot wiki, you first must have joined wikidot itself and have a wikidot account.
If you know the person who owns the wiki, they may invite you. If this happens, you will receive a notification that pops up on the next wikidot page you load. To accept the invitation, simply press the "Accept Invitation" button.
There is a link-button right from this "accept invitation" where you can refuse this invitation. I had never such an experience but technically this is possible.
This invitation is possible over e-mail too, if you have never heard from wikidot and the inviting site. Then you have to follow the link in the e-mail and (in most cases) have to create an account.
On the page "Join this site" or sometimes on the welcome page their is the posssibility to apply for admission - if the admins have allowed this. In this case you should have an account on wikidot (if you are an anonymous than the "Join this site" screen changes to the "Login/ Create an account" ) and type in a short text with your applyment for admission. Do not forget to click on the Apply-Button!
An admin can install a "general" password in the Site manager / members / policy page and allow the use of it. If you got such password (by mail or private message) you have the allowance to join the site as a member and can type this pasword here to get the entrance. Once you are a member of a site you will not need this password again to join.
If the wiki administrator has set their site's access policy to be 'open' and has added a Join button to one of their pages, you can click this button and instantly become a member.
If you are not logged into a Wikidot account, it will even take you through the steps of creating one! :)