Starting with Windows 10, version 1809,  the Windows Preinstallation Environment (PE) is released separately from the Assessment and Deployment Kit (ADK).

Refer to : Microsoft docs

To add Windows PE to your ADK installation follow the following steps:

1) Download the following installers from the Microsoft docs:

• Windows ADK for Windows 10, version 1809
• Windows PE add-on for the ADK

2) Install the Windows ADK for Windows 101809.

3) Run the Windows PE add-on for the ADK installer.

The WinPE files are installed at same location as they were in previous ADK installs.