this code reads texts of PDF file

pdf_string.swift

import Cocoa
import Quartz

var str = "Hello, playground"

let urlStr = "/absolute/path/to/your/pdf-file.pdf"
let url = URL(fileURLWithPath: urlStr)

// see https://developer.apple.com/documentation/pdfkit/pdfdocument
let pdf = PDFDocument(url: url)!
pdf.pageCount
pdf.string

// see https://developer.apple.com/documentation/pdfkit/pdfpage
let page = pdf.page(at: 0)!
let pageStringArray = Array(page.string!)

// get string locations
pageStringArray[0]
page.characterBounds(at: 0)
page.characterIndex(at: NSPoint(x: 85.441, y: 712.818))

// pageStringArray[110] this causes an error : index out of range (depending on your PDF test length)
page.characterBounds(at: 110) // Even if the 110th char does not exist, this returns NSRect