Some companies do great on mobile while others perform quite poorly. If you have significantly worse mobile than desktop data, we'll how an alert on your dashboard. Just click on the alert to go to the campaign screen.
On the campaign screen, look at the "Settings and Performance" column for gear icons with the red warning label. Click on the icon to view more details.
Within the data, open your Device Performance data. This will compare your desktop to your mobile traffic so you can understand the difference in metrics. If you want to disable mobile performance or add a negative bid modifier, navigate to your Device Tab within your Google Ads account to make bid adjustments or disable mobile devices from showing your ads.