| UUID | uuid | string |  | Universally Unique Identifier. | 
| Date | date | cal.Date |  | When the advance was made. | 
| Key | key | cbc.Key |  | The payment means used to make the advance. | 
| Reference | ref | string |  | ID or reference for the advance. | 
| Grant | grant | boolean |  | If this “advance” payment has come from a public grant or subsidy, set this to true. | 
| Description | description | string | true | Details about the advance. | 
| Percent | percent | num.Percentage |  | Percentage of the total amount payable that was paid. Note that multiple advances with percentages may lead to rounding errors, especially when the total advances sums to 100%. We recommend only including one advance with a percent value per document. | 
| Amount | amount | num.Amount | true | How much was paid. | 
| Currency | currency | currency.Code |  | If different from the parent document’s base currency. | 
| Card | card | pay.Card |  | Details of the payment that was made via a credit or debit card. | 
| Credit Transfer | credit_transfer | pay.CreditTransfer |  | Details about how the payment was made by credit (bank) transfer. | 
| Extensions | ext | tax.Extensions |  | Tax extensions required by tax regimes or addons. | 
| Meta | meta | cbc.Meta |  | Additional details useful for the parties involved. |