Just link the wiki here. And by default you should be able to edit all pages. Maybe your wiki has an overzealous admin. But we won't be able to say for sure until and unless you give us a link to the wiki.
The default protection, as AzureKesil said, is no protection. However, wikis may choose to require users to be autoconfirmed (account is at least 96 hours old) in order to edit. For wikis that are likely to attract a lot of underaged viewers (such as Disney Wiki, Wings of Fire Wiki, Adopt Me! Wiki), Fandom takes this choice away from the wiki and just enables it themselves.
Apologies, my previous post was inaccurate. The option that most wikis have it to allow/disallow anonymous editing. The part about requiring autoconfirmation has to be done by Fandom. Either way, the fact remains that some wikis have it and some don't.