https://github.com/apple/swift-markdown

import Markdown

let source = "This is a markup *document*."
let document = Document(parsing: source)
print(document.debugDescription())
// Document
// └─ Paragraph
//    ├─ Text "This is a markup "
//    ├─ Emphasis
//    │  └─ Text "document"
//    └─ Text "."

is anyone know how to use this package to render markdown text in SwiftUI or UIKit?

If you just need simple Markdown rendering (i.e., not something like tables or codeblocks) you can just use AttributedString. I don't know the full range of markdown supported by AttributedString off the top of my head, but it shouldn't be too hard to find out.

Instantiating Attributed Strings with Markdown Syntax | Apple Developer Documentation

Both SwiftUI and UIKit can handle AttributedString, although UIKit may require it to be converted to NSAttributedString first; I dunno.