Talk to organizers at a venue where the choir has performed. Ask them about the process of bringing in the choir, such as how they handled payment issues and ticket sales and if there were any logistical requirements, such as dressing rooms, host stays for choir members and meals.
Speak to other authorities and organizers at your church to make sure you have support for bringing in the choir.
Review the choir's website or written materials to find contact information for the performance manager and conductor. Contact the conductor or performance manager to find out what the choir's requirements are. Agree to one or two potential performance dates.
Extend a formal invitation to the choir if the church leaders agree to the performance date and choir requirements. Stay in touch as the concert date approaches.