即menu

import SwiftUI

struct menuView: View {
    var body: some View {
        NavigationView {
            ZStack {
                VStack{
                    Text("this is a test")
                }
            }
            .navigationTitle("My custom title")
            .toolbar {
                ToolbarItemGroup(placement: .navigationBarTrailing) {
                    Menu {
                        Button(action: {}) {
                            Label("Create a file", systemImage: "doc")
                        }
                        
                        Button(action: {}) {
                            Label("Create a folder", systemImage: "folder")
                        }
                    } label: {
                        Label("Add", systemImage: "ellipsis.circle")
                    }
                }
            }
        }
    }
}

这就是Menu。
根据Apple Developer Documentation，下面是一个用法示例：

Menu("Actions") {
    Button("Duplicate", action: duplicate)
    Button("Rename", action: rename)
    Button("Delete…", action: delete)
    Menu("Copy") {
        Button("Copy", action: copy)
        Button("Copy Formatted", action: copyFormatted)
        Button("Copy Library Path", action: copyPath)
    }
}

如果您希望打开菜单的按钮成为SF符号，就像有三个点的椭圆，您可以稍微不同地调用Menu：

Menu {
     // Add options here...
} label: {
    Image(systemName: "ellipsis.circle")
}