Czech individual businessmen and companies become VAT payers when their sales during any 12 months cross the amount of 1.000.000 CZK.

Another reasons are connected to making business with abroad:
— buying abroad goods for over 326.000 CZK;
— receiving services from foreign business;
— granting services to business from another EU-state.

With the last three reasons, you could chose between to become VAT payer or Identified person to VAT. The sense of Identified person status is, that you are regarded as VAT payer only for abroad transactions, without impact on the balance. Doing business within Czech Republic you are than a non-payer.

The companies want to be VAT-payers voluntarily when they have mainly corporate clients, which tend to place orders by another VAT payers.