I bought a dryer. It came with a 1/2" OD , 1/2" MIP x 3/8" FIP 48" length line. My home gas line is 1/2" with an elbow that takes a 5/8" flare. How can I adapt it?

Where the gas line ends, put on a 3/8" ODF flare gas valve with ball-type valve. This will fit the standard 3/8" ODF flexible gas lines sold, or you can go with 1/2" if you want.