Hello,
You have to use the charastics in order to generate your 3 products variants.
=> Have a look on this
tutorial
about Variants.
Create a Characteristics called by example "Version", and fill it with these 3 Values, "physical", "digital" & "bundle".
Then in your product in Specification part, add your "Version" Characteristic, define the default value version, and Save.
You have the Variant tab, and complete your variant product with required elements as :
- Physical with some weight datas
- Digital without weight BUT the relative PDF File (in Images & Files part)
- Bundle wih weight AND PDF file
Hope this will fit your needs
Regards