The UN explains:
Investments in infrastructure – transport, irrigation, energy and information and communication technology – are crucial to achieving sustainable development and empowering communities in many countries. It has long been recognized that growth in productivity and incomes, and improvements in health and education outcomes require investment in infrastructure.
The UN has defined 8 Targets and 12 Indicators for SDG 9. Targets specify the goals and Indicators represent the metrics by which the world aims to track whether these Targets are achieved. Below we quote the original text of all Targets and show the data on the agreed Indicators.