<div class="row">
    <div class="col-md-6">
        <mdb-select [options]="optionsSelect" [multiple]="true" placeholder="Choose your option"></mdb-select>
        <label>Example label</label>
    </div>
</div>

@Component({
  selector: 'multiple-material-select-example',
  templateUrl: 'multiple-material-select.html',

})

export class MultipleMaterialSelectComponent implements OnInit {

    optionsSelect: Array<any>;

    ngOnInit() {
        this.optionsSelect = [
            { value: '1', label: 'Option 1' },
            { value: '2', label: 'Option 2' },
            { value: '3', label: 'Option 3' },
        ];
    }

}