Try this:
DECLARE @tmp TABLE(TraType INT, TraName VARCHAR(50))
INSERT INTO @tmp (TraType, TraName)
VALUES(1, 'Internal transfer'), (2, 'External transfer')
SELECT t1.TraAsset, t1.TraType, t2.TraName, t1.TraDate, t1.TraFrom, t1.TraToTranCompanyID
FROM Transfers AS t1 INNER JOIN @tmp AS t2 ON t1.TraType = t2.TraType
WHERE t1.TraApprvBy is not null and t1.TraApprvDate is not null and t1.TranStatus='Approved'