remove border bottom in ion header

For ionic 5, it should be

<ion-header class="ion-no-border"></ion-header>

In ionic 2/3 border will be removed by using ionic-header no-border.

<ion-header no-border> </ion-header>

In ionic 5 border will be removed by using class="ion-no-border".

<ion-header class="ion-no-border"></ion-header>

No problem,

Just add this to your custom CSS:

.bar-header {
    border: 0px !important;
    border-bottom-color: transparent !important;
    background-image: none !important;
    border-bottom: none !important;
}