Hi,
If you sell ebooks, then these would normally be at the zero rate of VAT. You can see guidance here:
E-publications
We cannt comment on the liability of these digital products in other member states.
If these supplies do carry a VAT liability in other member states then there could be a requirement to register for VAT in the member states where they are supplied.
There is an option throughout the EU to sign up to the Non-Union VAT MOSS Scheme.
Please see below:
The place of supply of digital services
However if you are selling via a platform please see the information here:
Digital portals, platforms, gateways and marketplaces
Thank you.