Open the Contacts app on your phone
Make sure you are signed in to your Google account
Go to Contacts settings
Select Export contacts if you want to save them first
Choose your Google account as the destination
Turn on contact sync for your Google account
On Android, go to Settings
Tap Accounts or Passwords and accounts
Select Google
Choose your Gmail account
Turn on Contacts sync
Open the Gmail app or Google Contacts app
Verify that all contacts appear in Google Contacts
On iPhone, go to Settings
Tap Contacts
Tap Accounts
Select Gmail
Turn on Contacts
If needed, add your Google account first
Import contacts from SIM or phone storage into Google Contacts
Use Google Contacts on a computer to manage and confirm saved contacts
Wait for sync to complete
Check Gmail contacts from contacts.google.com