I wonder what kind of morphs you want for the plastic bag?
what you are going to do with it?

to make morphs you need to use Zbrush or you can use deformers in daz but Zbrush is a better option.

but also you may be able to avoid morphs entirely if you use d-force or smoothing modifiers

But again, it depends on what you want to do and what kind of plastic bag you want to have.