結果

html

<form (ngSubmit)="onSubmit()" [formGroup]="form">
    <ng-container formArrayName="defaultArray">
        <ng-container *ngFor="let item of defaultList.controls;let index = index" [formGroup]="item">
        <p>{{index + 1}}</p>
        <div class="form-group text-left">
            <label for="name">姓名</label>
            <input type="text" class="form-control" id="name" placeholder="姓名" name="name" formControlName="name">
        </div>
        <div class="form-group text-left">
            <label for="job">職位</label>
            <input type="text" class="form-control" id="job" placeholder="職位" name="job" formControlName="job">
        </div>
        </ng-container>
    </ng-container>
    <button mat-flat-button class="mb-3 align-items-center" color="primary" (click)="addDefault()">
    <mat-icon [inline]="true">add</mat-icon>新增
    </button>
    <hr>
    <button type="submit" class="btn btn-master" [disabled]="form.invalid">送出</button>

    {{form.value | json}}
</form>

ts

form = new FormGroup({
    defaultArray: new FormArray([
        new FormGroup({
            name: new FormControl(''),
            job: new FormControl(''),
        })
    ])
});

get defaultList() {
    return this.form.get('defaultArray') as FormArray;
}

addDefault() {
    this.defaultList.push(new FormGroup({
        name: new FormControl(''),
        job: new FormControl(''),
    }));
}