Magento 2 by default has only the data-structure for regions/states without any administration capabilities. Also, the city field is displayed as text-input leading typos & invalid addresses.
I have found a great extension to solve the limitations imposed by input city field
With this extension, store admin can easily manage both regions & cities from the backend UI. And the list of cities which are managed from the backend will be shown as a select dropdown to the customer during checkout & address management. This will not only avoid the typos/invalid address issue but also help the store owner to target the cities for shipping rates and cart rules.