Once a DVD has been recorded can you add data to it?
It depends...if you are burning data to a DVD-RW disc on a
computer, and you do not finalize the disc then you may add more
data later.
However, if you are using a DVD-R disc then it will need to be
finalized to access the files, and you will not be able to add more
data without first erasing the data that is currently stored on the
disc.