What are the main functions provided by iCloud on my iPhone?

Here are the main functions provided by iCloud on your iPhone:

• Profile - Manages your Apple ID profile.
• Family Information - Shares information with other Apple ID accounts in your family.
• Storage - Manages your storage in iCloud.
• iCloud Drive - Controls accesses for apps to store data in iCloud.
• Photos - Manages Photo Library, Photo Stream and Photo Sharing services. in iCloud
• Mail - Controls access to your email box in iCloud.
• Contacts - Controls access to your contacts iCloud.
• Calendars - Controls access to your calendar events in iCloud.
• Reminders - Controls access to your Reminders in iCloud.
• Safari - Controls synchronization of Safari data in iCloud.
• Notes - Controls synchronization of Notes in iCloud.
• News - Controls access to News in iCloud.
• Wallet - Controls access to wallet in iCloud.
• Backup - Manages auto backup of your iPhone to iCloud.
• Keychain - Manages Keychain service in iCloud.
• Find My iPhone - Manages "Find My iPhone" service in iCloud.
• Share My Location - Manages "Share My Location" service in iCloud.

The picture below shows you iCloud main functions on iPhone:

⇒ Update Apple ID Account from iCloud on iPhone

⇐ Sign Out from iCloud on iPhone

⇑ Using iCloud on iPhone

⇑⇑ Apple iCloud - Frequently Asked Questions