I din't find an easy way to create a SwiftUI TextField which gives the user autocompletion in the sense of filling the TextField with the completion word and highlighting the suffix, so the user can type uninterruptedly, but if there is a suggestion it will be filled in. Here is a simple implementation of this for a SwiftUI TextField:
import SwiftUI
struct SuggestionTextField: View {
let name: String
@Binding var text: String