Save custom field for a customer with ACF metafields

7 0 5

I have created a custom field "phone" using the app Advanced Custom Field. I can display this metafield just fine in the my accounts page using the code 


{{ }}


But I need to save this field in customer registration form. I added this code to save it 


<input type="text" class="form-control" id="register_phone_number" name="" value="" required placeholder="Enter Phone Number" />   


But it does not save the data in the field. How can I fix this?