How can i set a format?

[lXSPandora]

Hello,
How can i set a format to the datepicker to pick the data like yyyy-mm-dd.

Example
2017-08-14

[mmazzarolo]

Hello @lXSPandora, this is more a Javascript related question then a react-native-modal-datetime-picker one.
You should handle the date formatting on your own component.
The date returned by react-native-modal-datetime-picker is a plain JS Date object so you can format it using the plain JS Date API, date-fns, Moment.js and similar libraries.