Install the Apple Invites app on iPhone or use it on iCloud.com
To get started with Apple Invites, install the app on your iPhone or sign in to your Apple Account on iCloud.com.
For more details about Apple Invites and what you can do with it, see Introduction to Apple Invites.
Install the Apple Invites app on iPhone
Go to the App Store app
on your iPhone.Search for Invites
, then tap Get.If necessary, use Face ID, Touch ID, or your password to install the app.
Note: The availability of the App Store varies by country or region. See the Apple Support article Availability of Apple Media Services.
Use Apple Invites on iCloud.com
Go to icloud.com/invites, then sign in to your Apple Account (if necessary).
Tip: If you’re already on iCloud.com, you can also select 
in the toolbar, then select Invites.
Access your events in the app and on iCloud.com
To access the same events in the app and on iCloud.com, make sure Apple Invites is turned on in iCloud settings.
On your iPhone, go to Settings > [your name] > iCloud.
Tap See All, then turn on Invites.