Different users have access to different functions of the site. While anyone can do most things on the site, including reading and editing, an Administrator or sysop (system operator) is a trusted user that can access a few additional functions.
Deleting and undeleting pages, uploaded images and page histories.
Protecting a page so it can not be edited or moved by anonymous users (autoconfirmed protection) or non-admins (full/sysop protection).
Blocking IP addresses or usernames from editing; and quick reversion ("rollback") of undesirable edits.
Editing the interface by changing system messages and skins (editing MediaWiki files).
These functions are solely for housekeeping for keeping Wikia nice and tidy. The community does look to administrators to perform the essential chores that require the extra access Administrators are entrusted with. However, otherwise, Administrators are the same as other users, and are expected to be well-tempered in all respects.
Every founder of a Wikia has bureaucrat access on the wiki they founded. Other users may also be granted this access, by the founder, or by another bureaucrat. Bureaucrats also have admin rights, which enables access to most wiki management tasks. Semi-active bureaucrats often don't edit on the wiki anymore, but almost always respond back relatively quickly if you leave a message on their message wall.
To become an administrator or bureaucrat, one has to be a dedicated editor and have good wikia skills in general. If you see yourself fit to be an administrator, go here.
Wiki Helpers & Staff
The Fandom Helper Group is made up of contractors and volunteer interns working for Fandom. Depending on their specific role, they may be able to help with your wiki's design, Search Engine Optimization (SEO), and other means of supporting you and the Fandom community. Of particular note are Wiki Managers, who are part-time staff members assigned to specific wikis and who serve as liaisons with a direct line of contact to full-time Fandom staff.
Helpers have global administrator rights, but they do not outrank administrators. Helpers respect local wiki policies, and they will listen and respond to the views of any community they are working on and helping with.