HTML

ion select

<ion-select >
	<ion-select-option *ngFor="let country of countries" value="{{ country.name }}">
		{{ country.name }}
	</ion-select-option>
</ion-select>

ionic select

<ion-select placeholder="Select One">
  	<ion-select-option value="f">Female</ion-select-option>
	<ion-select-option value="m">Male</ion-select-option>
</ion-select>

ion select

 <ion-select >
          <ion-select-option *ngFor="let country of countries" value="{{ country.name }}">
            {{ country.name }}
          </ion-select-option>
     </ion-select>