Whenever you attempt to make a transaction, the merchant will "authorise" the transaction amount to confirm your card is valid and that there is enough balance on the card. The authorisation hold happens instantly after you make a transaction and is immediately visible in the Neat Business App.
For most transactions, the merchant will settle the payment within 1-3 days meaning the funds would actually transfer to the merchants' account.
If the merchant does not claim or settle the amount, the authorisation hold (amount placed on hold) will be automatically released in 28 days. This happens if you, for example, link your card to a service such as iTunes, where the merchant authorises a small amount to check whether your card is valid but does not settle the amount.