Is there a way to turn off cloud prompts on iPhone?

Hello Pvzee,

Thanks for posting in the Apple Support Communities. The prompt that you need more storage isn't one you can turn off. If you're using iCloud currently then you will receive that prompt when you're running out of storage. We recommend going through your iCloud storage and seeing if there is anything you can delete like duplicate photos, etc.

"Reduce the size of your iCloud Backup

When you back up your iPhone, iPad, or iPod touch to iCloud, the most important information on your device is backed up automatically. Learn more about what iCloud backs up.

Many apps automatically back up to iCloud after you install them. You can decrease the size of your iCloud Backup and free up space in iCloud when you stop backing up apps that you don't use or delete old iCloud backups. 

Choose which apps to back up on your iPhone, iPad, or iPod touch

1. Go to Settings > [your name] > iCloud.
2. Tap Manage Account Storage or tap Manage Storage, then tap Backups.
3. Tap the name of the device that you're using.
4. Turn off any apps that you don't want to back up.
5. Choose Turn Off & Delete.

When you confirm that you want to Turn Off & Delete an app, it turns off iCloud Backup for that app and removes all of its information from iCloud."

More ways to free up space can be found in this article: Manage your iCloud storage - Apple Support

Cheers!