You can use the IBM-supplied source file QTXTSRC to help you create and update online documentation.
You can create and update QTXTSRC members just like any other application (such as QRPGSRC or QCLSRC) available with the source entry utility (SEU). The QTXTSRC file is most useful for narrative documentation, which can be retrieved online or printed. The text that you put in a source member is easy to update by using the SEU add, change, move, copy, and include operations. The entire member can be printed by specifying Yes for the print current source file option on the exit prompt. You can also write a program to print all or part of a source member.