When the Windows 10 May 2019 Update is ready for your device, it will be available to download from the Windows Update page in Settings. Choose a time that works best for you to download the update. You'll then need to restart your device and complete the installation. After that, your device will be running Windows 10, version 1903.(To check whether you're already running the May 2019 Update, select View update history on the Windows Update settings page.) Also note the following:
If you want to install the update now, select Start > Settings > Update & Security > Windows Update , and then select Check for updates. If updates are available, install them.
If version 1903 isn't offered automatically through Check for updates, you can get it manually through the Update Assistant.