ng-pick-date picker : How to set date format?

You need to create another input which will display formated date value. In your html create one input for [ngModel] and another one to display formatted date value.

<div class="date-container">

 <!-- Invisible input keep ngModel value -->
  <input
          class="shadow-input"
          name="date_time"
          [(ngModel)]="currentDate"
          [owlDateTime]="dt1"

  >
  <!-- Trigger owl-datepicker, display formatted date value -->
  <input
          type="text"
          [owlDateTimeTrigger]="dt1"
          placeholder="Date Time"
          [value]="currentDate | dateFilter:dateFormat"
  >

  <owl-date-time #dt1></owl-date-time>
</div>

See demo on stackblitz

you have to pass the custom object to the service through provider useValue

export const MY_CUSTOM_FORMATS = {
    parseInput: 'LL LT',
    fullPickerInput: 'LL LT',
    datePickerInput: 'LL',
    timePickerInput: 'LT',
    monthYearLabel: 'MMM YYYY',
    dateA11yLabel: 'LL',
    monthYearA11yLabel: 'MMMM YYYY',
};

selector: 'app-custom-format-example',
templateUrl: './custom-format.component.html',
providers: [ 
    {provide: OWL_DATE_TIME_FORMATS, useValue: MY_CUSTOM_FORMATS},
],

check the demo