Example of custom styles using Markdown support in SwiftUI Text.

MarkdownExample.swift

import SwiftUI
import PlaygroundSupport
import Foundation

struct MarkdownView: View {
    var body: some View {
        Text(try! AttributedString(markdown: "This is a **basic** _string_. Italic bits are red. All the **bold** bits are _coloured_ **green**! And [this is a link!](https://q42.nl/).", customBoldColor: .green, customItalicColor: .red))
            .font(.title)
    }
}

extension AttributedString {
    init(markdown: String, customBoldColor: Color, customItalicColor: Color) throws {
        try self.init(markdown: markdown)
        for run in runs {
            // Apply different styles for bold and italic text
            switch run.inlinePresentationIntent {
            case InlinePresentationIntent.stronglyEmphasized:
                self[run.range].foregroundColor = customBoldColor
            case InlinePresentationIntent.emphasized:
                self[run.range].foregroundColor = customItalicColor
            default:
                break
            }
            
            // Add underline to links
            if run.link != nil {
                self[run.range].underlineStyle = .single
            }
        }
    }
}

PlaygroundPage.current.setLiveView(MarkdownView())