The name Common Grant Application is misleading. It is not a simple application for grant seekers to fill in. Rather, it is a general outline for grant seekers to use when crafting their proposals.
The Foundation Center describes how to use the Common Grant Application:
“The common grant application format has been adopted by groups of grantmakers to allow grant applicants to produce a single proposal for a specific community of funders, thereby saving time. Before applying to any funder that accepts a common grant application form, be sure to check that your project matches the funder’s stated interests, and ascertain whether the funder would prefer a letter of inquiry in advance of receiving a proposal. Also be sure to check whether the funder has a deadline for proposals, as well as whether it requires multiple copies of your proposal.”
Here is the Common Grant Application for Grantmakers of Western PA. On page 9, there is a list of the grantmakers who accept this format.