以下のような文章が来て添付ファイルがアドビのアクロバットリーダーでついてきましたが、意味が用判りませんので教えてください。電子証明を要求してきて、それを送るとどうなるのかが、しりたいのです。更に関税をとられるようですと価格を大幅に上げないとできないのです。


Dear Surugajino Samueya,
Please find enclosed an electronic tax invoice for the month of 5/2018 in PDF format. Please note that this invoice is not a request for payment.
To review your account summary or request other copies of your tax invoices, please log into your Seller Central account.
If you have any questions, please contact Seller Support.
Best regards,
Amazon Services Europe
An advanced electronic signature has been attached to this electronic tax invoice. To add the certificate as a trusted certificate, please follow these instructions:
1. Click on the 'Signature Panel' in the upper right corner.
2. Expand the drop-down in the newly opened Signatures menu, expand the 'Signature Details' drop-down and click 'Certificate Details'.
3. In the Certificate Viewer box click on the 'Trust' tab, click 'Add To Trusted Certificates' and then click OK.
4. In the Import Contact Settings box, ensure that 'Use this certificate as a trusted root' is selected, click OK, and then click OK again.