They can take a correspondence program like Moody's or Liberty's. They can go away to a Bible college or institute. Some Bible institutes are started by one church for the purpose of providing training for its membership. Some are started by one church, but an attempt is made at providing a service to other churches in the community. Some institutes are actually formed cooperatively by several churches working together.
Some institutes are primarily an extension program of a Christian college.
There are also correspondence institutes available like the Liberty program and the one from Moody that are primarily designed for individual study. Bible study is a major part, and courses could be offered on Bible survey, Bible book studies, Bible doctrine, Bible geography, Bible archaeology, and Biblical introduction. How to serve type courses could be offered on Sunday School, bus ministry, Vacation Bible School, children's church, music, Awana, evangelism, and missions. Materials to use for curriculum are available from many sources. Dr. Harold Wilmington at Liberty University is making available a local church Bible institute program in a package for a church.