Attribution
Attribution is working out where each person came from before they installed your app: a search, a link, an ad or another app.
Also called Install source, Where users come from.
In plain words
Most people found Fern by searching the App Store; a link on a gardening blog brought the ones who paid most.
How Apparent would say it about Fern, an example app in the live demo.
Good to know
The stores tell you where downloads came from in broad groups. Apple's App Analytics splits them into App Store search, App Store browse, web referrers and app referrers. Google Play gives similar groups.
Ad networks and attribution tools go further and match each install to a click on an ad. That needs their SDKs and, on iOS, Apple's privacy rules limit what can be matched to a person.
For most small apps the store's groups answer the real question: is search working, and which websites send people who stay?
Where the number comes from
App Store Connect and Google Play for store sources; your app or RevenueCat for sources it records.