HEDIS ECDS technical specifications are available in the NCQA store in PDF format: http://store.ncqa.org/index.php/catalog/product/view/id/2822/s/hedis-2018-volume-2-measures-for-electronic-clinical-data-systems/. They are also available in HEDIS 2018 Technical Specifications for Health Plans, which can be purchased at the NCQA store.
Complete digital measure packages for HEDIS ECDS measures will be available for download at a future date.
HEDIS 2018