Use HASHBYTES(). Here is an example from https://docs.microsoft.com/en-us/sql/t-sql/functions/hashbytes-transact-sql?view=sql-server-ver15
DECLARE @HashThis NVARCHAR(32);
SET @HashThis = CONVERT(NVARCHAR(32),'dslfdkjLK85kldhnv$n000#knf');
SELECT HASHBYTES('SHA2_256', @HashThis);