That's a very good initiative your mother is taking. To register the nonprofit organization, you need to do the following things:

You need to incorporate with your state's Secretary of State. Apply for an EIN (Employer Identification Number). The IRS issues this number. File IRS Form 1023 (or 1023-EZ). The difference depends on the annual gross receipts.

If the forms are approved, then the IRS sends the "Determination Letter" and confirm 501(c)(3) tax-exempt status. Once you get this status, then you need to separately apply for state-level tax exemptions. Once 501(c)(3) status is granted, your organization enjoys significant tax benefits.

About the tax implications:

Your organization needs to file the annual IRS returns (Form 990 series). Benefits include tax exemption and deductible donations.