Then read this article and Apply the below instructions:
Step 1: First of all, open the Settings of your iPhone.
Step 2: Tap on Mail, Contacts, Calendars.
Step 3: Tap on Accounts icon.
Step 4: After that, tap on Add Account option.
Step 5: Tap on the Google.
Step 6: Enter your Gmail ID under the Username.
Step 7: Enter your password under the Password.
Step 8: Type Google Calendar under Description.
Step 9: Tap on the Next.
Step 10: Now ensure that Calendars is ON and then tap on the Save to complete the procedure.
Are you not competent enough to add Google Calendar to iPhone with the help of above instructions? Then dial Google Technical Support Phone Number and avail the reliable technical assistance from the experts, who are well trained and certified. You can dial these numbers 24/7 hours and fix all your issues in a perfect manner.