The choice of service and venue should be decided by lottery, so you can choose service or venue freely, right?

Generally, throwing the ball is used. The two sides stand on one side of the net, and the referee throws a good badminton vertically to see who the ball is facing when it lands.

The party facing the tee has the right to choose whether to serve first or choose the venue (note that it is not necessary to decide only to serve, and both the server and the receiver can score points under the per-ball scoring system, so they can also choose to receive the service first), while the other party can only accept another condition.

Another way is to flip a coin. Both sides choose one side of the coin, and the specific process is similar to the last one.