CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies), especially in areas of significant community-based transmission.
CDC also advises the use of simple cloth face coverings to slow the spread of the virus and help people who may have the virus and do not know it from transmitting it to others.  Cloth face coverings fashioned from household items or made at home from common materials at low cost can be used as an additional, voluntary public health measure.
Cloth face coverings should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the mask without assistance.
The cloth face coverings recommended are not surgical masks or N-95 respirators.  Those are critical supplies that must continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance.
 
IMPORTANT:
Cloth face coverings/masks/respirators should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the cloth face covering without assistance. People with chronic respiratory, cardiac, or other medical conditions that make breathing difficult should check with their health care provider before using an Respirator Mask because a Respirator Mask can make it more difficult for the wearer to breathe. Some models have exhalation valves that can make breathing out easier and help reduce heat build-up. Note that Respirators Masks with exhalation valves should not be used when sterile conditions are needed.