[crazy]

If you need to restrict or give access to only certain things to players, either its from other plugins or just general minecraft permissions, you are best to add a "Permissions system plugin" on your server.
Many plugins have a permissions list which you can then use on a permissions system plugin to restrict or give access to players.

There are a few permission system plugins you can use, but all require a bit of time allocated to learn how to use and troubleshoot.

List of common permission systems:

Widley used: PermissionsEx: https://dev.bukkit.org/projects/permissionsex
Note: Works on Minecraft 1.13 but not officially supported.

Recent and updated: LuckPerms - https://www.spigotmc.org/resources/luckperms-an-advanced-permissions-plugin.28140/
Note: Official for v.1.13


Paid Plugin: UltraPermissions: https://www.spigotmc.org/resources/ultra-permissions.42678/
Note: There a paid plugin which uses the in-game interface to set up permissions - to some its much easier.

So for example, say you want WorldEdit to be restricted to only a few members, you first will need a list of all the permissions WorldEdit would support. You can google this but here is a list of WorldEdit's Permissions:
 http://wiki.sk89q.com/wiki/WorldEdit/Permissions