Are you interested in becoming an admin? If so, please first check whether the wiki's admins are active. If they are, you may need to wait until a new admin is needed.
In the meantime you can get to know the community by editing the wiki and reading any policy or other help pages. When you are an established member of the community, you may be invited to be an admin!
You can also try leaving a message for an active admin to let them know you are interested in helping out. Bigger communities often have request pages or nomination pages for this, but on smaller communities you can usually just approach an admin or the Founder.
If the wiki's admins are not active, you can ask to adopt the wiki. Please visit the adoption page for more information, including what you need to do to be eligible for adoption.