If the import declaration contained your EORI and postponed VAT accounting (PVA) was selected, you will need to sign up for the Customs Declaration Service (CDS) to be able to access electronic PVA statements.
Get your postponed import VAT statement
You can find guidance on accounting for import VAT on your VAT return here:
Complete your VAT Return to account for import VAT
If PVA was not selected, you can find guidance on obtaining C79’s here:
Check how to get your import VAT certificate (C79)
This would also require you to access CDS.