If you log on to E-tax for businesses using an E-tax password (TastSelv-kode), you can access everything in your tax account and in E-tax for businesses (TastSelv Erhverv) in general. So, logging on to E-tax for businesses with an E-tax password does not enable you to give specific employees certain, restricted rights.
However, using an E-tax password still allows you to give advisers or accountants access to your tax account.