This IRS page provides resources and tools for tax-exempt organizations relating to annual filing requirements and 990-series forms.
Form 990 must be electronically transmitted to the IRS (either directly, as an IRS-approved online provider, or indirectly, through an arrangement with an IRS-approved online provider). This enables all 990 Forms to be available in a “machine-readable” format so that the public can access and search these documents.
Form 990 IRS-approved Providers
These are some recommended Form 990 IRS-approved online providers. These are similar to a Turbo-Tax service where you are guided through the form and enter appropriate financial and other details. You can also upload docs.
Form 990 Online
File 990
Express Tax Exempt
Opening Form 990 by the Aspen Institute provides a good overview of Form 990 with filing information.