Please note that Other Taxes such as VAT or GST when set here will apply to ALL products in your feed. Should only select products require this tax you will need to use a Supplemental Feed in Merchant Center to adjust them.
For retailers (mostly) outside the US, the account-based Tax settings are not applicable.
To apply other taxes such as VAT or GST to your feed so that they match your store, simply fill in the percentage under Other Taxes:
Click Save, and then return the Feed Tool and send your feed to Google