When selecting a laundry detergent, it’s important to consider what type of washing machine you have, the water temperature you will use for washing, and how heavily soiled/stained your clothes are. Generally speaking, liquid laundry detergents can be used with energy-efficient machines that require cold water washes, while powdered forms work best for hotter temperatures and more heavily stained garments.
For my laundry soap recommendations, please check out the comments section for links.