According the the CDC:
Reported illnesses have ranged from mild symptoms to severe illness and death for confirmed coronavirus disease 2019 (COVID-19) cases.
The following symptoms may appear:
Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Muscle or body aches
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea
Children have similar symptoms to adults and generally have mild illness.
If you develop emergency warning signs for COVID-19 get medical attention immediately. Emergency warning signs include (but are not limited to):
Difficulty breathing or shortness of breath
Persistent pain or pressure in the chest
New confusion or inability to arouse
Inability to wake or stay awake
Blush lips or face