A city you can pin
Search for a city by name, then save its id so later lookups keep pointing to the city the user chose.
If someone picks Charlotte, North Carolina as their home city, that choice needs to survive the next time your app loads their profile. Searching for "Charlotte" again leaves the decision up to search results, even though the person already made it.
That's what the id on a city lookup is for. Here are the relevant fields from GET /city/charlotte?country=US:
{
"name": "Charlotte",
"state": "NC",
"state_name": "North Carolina",
"country": "US",
"id": "city_mb8mbqrkz8zb"
}
Save that id and fetch /city/id/city_mb8mbqrkz8zb when you need the record again. A population update or a change in search ranking won't make the saved choice point to a different Charlotte. The id stays with the record and is never reused for another city.
The name still comes first when someone is looking for a place. Nobody filling out a profile knows their city's ParseAPI id. Once they've chosen, though, there's no reason to keep asking the search engine the same question. Store the id alongside whatever label you want to display.