ReplicatedStorage
ReplicatedStorage is a general container service for objects that are available to both the server and connected clients. It is ideal for ModuleScript, RemoteFunction, RemoteEvent, and other objects that are useful to both server-side Scripts and client-side LocalScripts.
Objects parented to this service are fully replicated to clients and normal replication rules apply. Any changes that are made on the client persist but won't be replicated to the server, and client changes may be overwritten if the server does something that overwrites those changes.
LocalScripts do not run when parented to this service, even if they are Enabled; LocalScripts have various other locations where they eventually run on a Player client such as StarterPlayerScripts, StarterCharacterScripts, or StarterGui.
Similarly, Scripts do not run when parented to this service unless you change their Enum.RunContext property from the default value of Legacy. Server Scripts that run on their own should be parented to ServerScriptService instead.
If a ModuleScript within this service is required by any other script, it runs as normal. Such modules typically house code that is shared by the server and client.