what will dofor green phlgm

?What is the treatment of green phlegm
the treatment in your case depends mainly on the other associated symptoms such as dyspnea or something else and the cause but it's most likely due to bacterial infection , if it was bronchitis you will be prescribed to take antibiotic as Augmentin 1gm twice daily with a drug to take the sputum out such as tussibal while another strong antibiotic will be prescribed in case of pneumonia such as Levofloxacin once daily for 10 days , and till you visit the doctor you have to isolate yourself from family and friends to avoid spreading the infection cause it might be dur to Covid19 
What are the investigations you should have ?
first of all it's all about history and physical examination the the doctor will ask you to do CBC to look for WBClevel that may show significant increase in bacterial infections , and you have to have Chest xray to see the infiltrates in bronchus and lungs , if corona is suspected PCR is required too 
What are the causes of green Sputum ?
Bronchitis 
Pneumonia
Cystic fibrosis 
Corona 
Bronchectasis
Sinusitis 
Advice :
you have to ask for pulmonologist help