<form [formGroup]="myForm" (ngSubmit)="onSubmit()">
<ion-checkbox
formControlName="agree"
helperText="Agree to the terms before continuing"
errorText="You must agree to the terms to continue"
>
I agree to the terms and conditions
</ion-checkbox>
<br />
<ion-button type="submit" size="small">Submit</ion-button>
</form>