Windows Declarative Componentized Hardware (DCH) supported apps and drivers are driver packages that install and run on Universal Windows Platform (UWP) based editions of Windows.
Moving to DCH drivers is a requirement from Microsoft for anyone developing drivers for Windows going forward.
Dell supplies copies of the drivers that are used for all its computers on its support pages. Windows drivers are changing to DCH as they are developed and updated. There is a chance that you can have driver issues if you are unaware of this change that started with Windows 10 (version 1709). Regularly update your version of Windows and keep your drivers up to date as recommended by Microsoft and Dell.
All the driver vendors recommend upgrading from Legacy to Windows DCH drivers. They all point you to your computer manufacturer for the latest driver updates. (Dell Support Site.) Most vendors actively try and discourage you from going in the other direction. (Going from a DCH driver back to a Legacy driver.) Most driver vendors advise that it is a complex process that can result in system instability. Most have asked that you to contact them directly if you think you need to attempt it.
All the driver vendors recommend upgrading from Legacy to Windows DCH drivers. For some drivers, you may have to fully uninstall the Legacy driver from your computer before installing the Windows DCH driver.
Here are some external web pages that discuss this in more detail: