How do I get the calendar and email apps to sync between my MacBook Air and my iPhone and iPad?
[Re-Titled by Moderator]
Original Title: Syncing problems between apple devices
MacBook Air
You can synchronize calendars through iCloud, and through shared e-mail accounts. On a Mac, System Settings > Internet Accounts has entries for all of the Internet accounts that you have set up, and under each, you can control whether to synchronize the Mac's Mail, Contacts, Calendars, and Notes applications with that account.
Calendar User Guide for Mac - Apple Support
With e-mail, just set up your Mac, iPhone, and iPad to connect to the same e-mail accounts.
Add email accounts in Mail on Mac - Apple Support
Add an email account to your iPhone or iPad - Apple Support
You probably won't have to specify all of the details of the connection – like whether to use IMAP or POP3. If you are accessing email from multiple devices, you want IMAP. With IMAP, the master copies of your email live on the email provider's server – your Mac, iPhone, and iPad may store cached copes, but they won't fight each other, to see who can grab a particular email and delete it from the server before the others can see it.
You can set up an iCloud Mail account, but this is not a requirement.
Send and receive iCloud Mail on all your devices and keep Mail settings up to date - Apple Support
Set up iCloud Mail on all your devices - Apple Support
The key is just to connect all of your devices to your e-mail accounts, and let email synchronize through your email providers (e.g., Apple for iCloud Mail, Google for Gmail, etc.).
How do I get the Calendar and Mail apps to sync between my MacBook Air, iPhone, and iPad?
