How do I add VAT to product prices in my UK store?

When adding products to my store, do I add the products with the price including VAT or excluding VAT?

We are in the UK so have a VAT number.

Do I need to tick/untick anything on the product page or settings?

Thanks!

@TileOutlets
Settings-> Taxes and duties →

Yes, I have all these ticked…

product listing…