I need VAT invoices for my purchases please.

Welcome to the Apple Community.

Apple Do not ordinarily issue VAT invoices since the vast majority of products from the iTunes store are for non-commercial use. They are however required to provide one upon request.

You should request your invoice through iTunes Store SupportThey may, however, be reluctant to provide you with a VAT invoice at first, so you should be willing to point them to their obligation to do so, evidence of which can be found on HMRC's website.