You can use the .font() modifier to set the font of a text view in SwiftUI. If you want to use different fonts depending on the current locale, you can use the .environment(\.locale) modifier to get the current locale, and then use an if statement or a switch statement to choose the appropriate font based on the locale.

For example:

Text("Hello")
  .font(.system(size: 20))
  .environment(\.locale) { locale in
    if locale == Locale(identifier: "fr_FR") {
      return Font.custom("Avenir", size: 20)
    } else {
      return Font.custom("Helvetica", size: 20)
    }
  }

This will use the "Avenir" font for French locales, and the "Helvetica" font for all other locales.