SMB is the Server Message Block protocol, the default file-sharing protocol for Microsoft Windows, and also for macOS for the past several years. It can also be used with Unix-y clients (Linux, FreeBSD, etc.), though NFS may be a better choice for those clients. It's very likely you'll want to enable this service and at least one share on your system.
To enable the SMB service in TrueNAS SCALE, in the web GUI, go to System Settings (1) -> Services (2).
Then check the box under Start Automatically for the SMB service, and move the switch under Running to start it.
In order to create a shared folder, you must first have at least one user on your system that isn't an administrator. If you don't already have such a user, you can create one under Credentials -> Local Users. Once you have such a user, create a shared folder, in the web GUI, click on Shares (1), then the Add button next to Windows (SMB) Shares (2).
Under Path, expand /mnt
, then choose your pool (1), then click on Create Dataset (2)
In the pop-up window, enter a name for the share, then click Create. The dataset will be created, and the share name (in the Name field) will default to the name you gave the dataset. Enter a Description if desired (it's optional), then click Save. Your shared folder will be created.
To enable the SMB service in TrueNAS CORE, in the web GUI, click on Services, then scroll as needed to find SMB in the list. Check the box to start automatically, and flip the switch to turn on the service.
In order to create a shared folder, you'll need to have already created a dataset to share. Then, in the web GUI, click on Sharing (1), then Windows Shares (SMB) (2), then Add (3).
Then navigate to the dataset you want to share, as shown below. The share name will default to the name of the dataset, but you can change it if desired. Enter a description if desired. Then click SUBMIT to create the share.