There are a number of rates of VAT depending on the type of supply
Standard rate = 20%
Reduced rate = 5%
Zero rate = 0%
Exempt = na
Outside the scope = na
With Zero, Exempt and Outside the Scope no VAT is charged; although the Zero rate is still a rate of VAT and input VAT incurred on making these supplies can be recovered in the same way as standard rated supplies.
If Exempt supplies are made, then there is no input VAT recovery on the costs in making those supplies.
Outside the Scope means that there is no supply for VAT purposes, and often this relates to donations received and supplies made outside the UK.
The rules for buying and selling to the EU and the rest of the World are complicated, so please follow the link to the section on Imports and Exports.