If you need to get the returned GUID uniqueidentifier after inserting a record. You cannot use the method  SCOPE_IDENTITY() to retrieve the value. What you can do is by creating a temporary table in TSQL as a variable table and then perform output to insert the column Guid into the table variable.

Let says we have the following user table.

Here is the TSQL query to insert a new record into the Users table in SQL Server.

DECLARE @UserId uniqueidentifier
DECLARE @GuidTable TABLE (
	ColGuid uniqueidentifier
)

INSERT INTO Users(
	FirstName,
	LastName,
	Email
)
OUTPUT inserted.UserId INTO @GuidTable
values(
	'Jack',
	'Anderson',
	'testingemail@example.com'
)

SELECT @UserId =  ColGuid FROM @GuidTable

If you have a look at the above query. Just between the Insert section and Values keyword. There is a query statement to output the inserted Guid into the variable table.
Then to get the value itself you can see the last query where we select the ColGuid from the variable table.