Those who have an iPhone or iPad are familiar with alerts but also with how annoying they can become. However Apple provides a unique location called "Notification Center", where you can view and manage your device alerts.
On iPhone and iPad, Notification Center is central interface for control of notifications in device you have received from applications or by the operating system itself system. To see the Notification Center while your iPhone or iPad is unlocked, swipe down from the center of the top edge screen. However, be careful not to drag down the top right edge of the screen, as on iPads and modern iPhones without a home screen button, this opens the Control centre. But from iOS 14 and iPadOS 14, you can also swipe down from the top left edge of your screen.

To view the Notification Center on the lock screen, swipe up from the middle of the screen until it appears. You can turn the Notification Center on or off the lock screen by going to Settings> Touch ID & Passcode or Face ID & Passcode.
You will then see a special screen titled "Notification Center" that displays recent notifications. If an application has sent more than one notification, the notifications may be stacked together. Tap the stack to see all notifications.

In Notification Center, you can swipe right on a specific notification to open it in the source application. If you swipe left, you can delete this alert. Alternatively, if you want to delete all notifications at once, press the small button "X" next to the heading "Notification Center" and then press "Liquidation".

You can also turn off some notifications from this screen by swiping your left finger on a notification bubble and tapping "Management" in the options that appear.

If notifications bother you, you can turn them off by application by going to Settings - Go to Settings> Notifications and then clicking on an application you want to manage. There, you can select the type of notifications you want to receive or turn off completely.
Photo source: howtogeek.com