How about something like this?
declare @x table (TransId varchar(10))
insert @x
(TransId)
values ('4461'),
('14130')
select TransId
,'CP' + right('000000000000' + TransId, 12)
from @x x
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.