Getting a chorus of voices going for your worship services is often considered a necessary element of worship. Some of the best kinds of church choir sheet music were once the province of certain groups and institutions. The sheet music was distributed through a network that was mostly geared for church groups.
It still works that way, although nowadays the groups have converted to online use. Other than that, the work done on the sheets of musical notes goes on in the same way. Reproduction can be part of an old printed item that has been around for some time, or it could mean new material in terms of design, fonts and arrangement.
Sheets can be reproduced for the older and established choral works. These were composed and written perhaps by classicists and masters, or in the modern sense professionals in academies of musical study and the like. Choral groups have their self made composition system worked for them or provided by their own special composers.
That is for new works, and the singing groups may combine new and old effectively. In any case they need the sheets to read notes when necessary, or perhaps for the use of an instructor or coach who knows how to read notes. Reading notes can be a thing for professional singers who can sing in choirs.
For churches, the need to do the reading lies mainly on the seniors, managers and the said coaches. The main singers may not even be able to understand what all the notations are for. And mostly, they are not persons who have trained and studied to become pros in the business of singing in churches.
They might be skilled or talented but the use of their voices is mainly for worship on Sundays. Practice may be done twice or thrice a week, with no time for studying how notes can be read off a sheet. So the thing is actually something compiled by the managers, treasured for what they bring into their system.
This is not expensive as a commercial product, and usually is highly accessible in this sense. But limitations in access include how choirs work with their own set items for exclusive use and may not share their materials. Musical companies or those producing the product under discussion may also limit their production.
Usage is more than just a means of making music, but making sound that counts in religious ceremonies. Any church can have a choir, and can use this, but they often go through their own paces, use their own systems. The usage of course is always tasked to help them find their way into the music and its use in ritual.
The sound therefore special to such groups, which could be untrained or have a minimum training process. The interest is good enough, and the willingness to go under instruction is needed. The musical items used are mostly used to enhance the singing and how it is coordinated and have certain voice runs and other factors that apply.