Set it up one time, and contacts sync automatically in the future.
To sync Google Contacts to your iPhone, check that your Gmail account is set up on your iPhone.
Scroll toPasswords & Accounts.
Turn on theContactstoggle switch.
You may see a message that saysTurning on Contacts.
When itdisappears, syncing is set up.
Any addresses you add to Google Contacts sync to your iPhone.
And, changes you make to those contacts on your iPhone automatically sync to your Google Contacts account.
After you’ve done that, go through this to set up syncing:
Open theSettingsapp on the iPhone.
You may be asked to enter the password for your Yahoo account.
You may see a message that saysTurning on Contacts.
With that done, syncing between the two accounts is set up.
Changes aren’t synced instantly, but you should see changes show up in a few minutes.
To turn off syncing, move theContactstoggle switch to Off/white.
SelectDuplicatesto determine if there are any duplicate contacts.
If you have duplicates, selectDismissto skip it orMergeto combine the contacts.
Repeat this process for all duplicates until none are left.
Resolve Duplicate Contacts in Yahoo Contacts
Go to YahooContacts.
jump in with your Yahoo account if prompted to do so.
Yahoo Contacts displays the duplicate contacts in your address book (if any).
Or, to or review each duplicate, select it and decide what you want to merge.
Repeat this process for all the duplicates until none are left.
