ScrollView programmatically. UIScrollView.

ScrollView.swift

import UIKit

final class DetailView: UIView {
  
  // setting up a scroll view
  // 1. add scrollview
  // 2. add content view
  // 3. add subviews to content view
  // Note: must set high priority of content view to low, default is 1000
  
  private lazy var scrollView: UIScrollView = {
    let sv = UIScrollView()
    return sv
  }()
  
  private lazy var contentView: UIView = {
    let view = UIView()
    return view
  }()
  
  public lazy var imageView: UIImageView = {
    let iv = UIImageView()
    iv.image = UIImage(systemName: "photo")
    iv.clipsToBounds = true
    return iv
  }()
    
  public lazy var descriptionLabel: UILabel = {
    let label = UILabel()
    label.numberOfLines = 0
    label.text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
    label.font = UIFont.preferredFont(forTextStyle: .title1) // title1, larger, title2 medium, title3 smaller
    return label
  }()
  
  override init(frame: CGRect) {
    super.init(frame: UIScreen.main.bounds)
    commonInit()
  }
  
  required init?(coder: NSCoder) {
    super.init(coder: coder)
    commonInit()
  }
  
  private func commonInit() {
    setupScrollViewContstraints()
    setupContentViewConstraints()
    setupItemImageViewConstraints()
    setupDescriptionLabelConstraints()
  }
  
  private func setupScrollViewContstraints() {
    addSubview(scrollView)
    scrollView.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      scrollView.topAnchor.constraint(equalTo: topAnchor),
      scrollView.leadingAnchor.constraint(equalTo: leadingAnchor),
      scrollView.bottomAnchor.constraint(equalTo: bottomAnchor),
      scrollView.trailingAnchor.constraint(equalTo: trailingAnchor),
    ])
  }
  
  private func setupContentViewConstraints() {
    scrollView.addSubview(contentView)
    contentView.translatesAutoresizingMaskIntoConstraints = false
    let heightConstraint = contentView.heightAnchor.constraint(equalTo: scrollView.heightAnchor)
    heightConstraint.priority = UILayoutPriority(250)
    NSLayoutConstraint.activate([
      contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
      contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
      contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
      contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
      contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
      heightConstraint,
    ])
  }
  
  private func setupItemImageViewConstraints() {
    contentView.addSubview(imageView)
    imageView.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
      imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
      imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
      imageView.heightAnchor.constraint(equalTo: safeAreaLayoutGuide.heightAnchor, multiplier: 0.50)
    ])
  }
  
  private func setupDescriptionLabelConstraints() {
    contentView.addSubview(descriptionLabel)
    descriptionLabel.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      descriptionLabel.topAnchor.constraint(equalTo: imageView.bottomAnchor, constant: 20),
      descriptionLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 20),
      descriptionLabel.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -20),
      descriptionLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -20)
    ])
  }
}

Thanks, that is what I am looking.

Glad it worked out for you 👍🏾

Good example 👍
Duplicate constraint at line 73
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),