Lucky Patchers are an app which allows you to install an OSM map from the internet.
The app is free, but the app is limited to one map per user.
Lucky Patches can also be purchased for $1.99 per month or $4.99 a year.
LuckyPatcherExpressVpn offers another option which lets you install OSMs from the same app.
Luckypatcher is a free download and has the same functionality as OSM Patchers, but is more limited.
It also has a limit of one map at a time.
The $4-per-month version of the app lets you download more than one map and has a maximum of three maps.
The monthly version of OSMPatcher has the ability to download additional maps from the App Store.
Both apps have the same price and offer a wide range of functionality.