Make payments online to the IRS for personal income taxes due
https://www.irs.gov/payments
Electronic Federal Tax Payment System (EFTPS) for business payments and estimated payments
https://www.eftps.gov/eftps/
W9 Form for Independent Contractors
https://www.irs.gov/pub/irs-pdf/fw9.pdf
IRS Tax Calendar and Due Dates for Businesses and Self Employed
https://www.irs.gov/businesses/small-businesses-self-employed/irs-tax-calendar-for-businesses-and-self-employed
IRS Charities and Nonprofits
https://www.irs.gov/charities-and-nonprofits
Check your refund status
https://www.irs.gov/credits-deductions/child-tax-credit-update-portal