WASHINGTON — The Internal Revenue Service today reminds tax-exempt organizations that operate on a calendar-year (CY) basis that certain annual information and tax returns they file with the IRS are due on May 17, 2021. These returns are: Form 990-series annual information returns (Forms 990, 990-EZ, 990-PF, 990-BL) Form 990-N, Electronic Notice (e-Postcard) for Tax-Exempt…