The YYYYMMDD format is very useful in organizing data for filenames, sorting, etc.

Here is one way to generate that  format.

SELECT CONVERT(VARCHAR(10), getdate, 112)

This is the method that works well in sql.  If you want to do the equivalent in an expression in SSIS then you can use the Year,Month,Day functions.

Year(getdate()) *10000 + MONTH(getdate())*100+ DAY(getdate())

This will result in a integer value in the form of YYYYMMDD.   You can then convert to a varchar.