The city of Los Angeles has launched a web portal where high-risk residents can sign up for testing. This applies to people with symptoms, or those who are 65 or older and/or anyone with underlying health conditions. First thing you need to do is complete this online questionnaire at: https://lacovidprod.service-now.com/rrs, this tool screens your symptoms and finds out if you're eligible for for a COVID-19 test.
Of course, if you're experiencing severe symptoms, such as severe shortness of breath, contact your doctor. If it is an emergency, dial 911.