All unflavored ground coffees are acceptable for Passover use when bearing an OU.
Coffee is often decaffeinated by means of ethyl acetate, which is derived from either kitniyot or chometz. Certain brands of decaffeinated coffee are approved when appearing a regular OU symbol. Please check the OU Passover product search or consult the OU Passover guide for a complete list.
Instant coffees often contain maltodextrin, which is derived from either corn (kitniyot) or wheat (chometz). Therefore, all instant coffees require special Passover certification. Please check the product search or consult the OU Passover guide for a complete list of instant coffees approved with a regular OU symbol.
Keurig Coffee Maker A number of Keurig / K cups are approved for Passover even though they are not labeled with a OU-P. A complete list is available on the oupassover.org search engine. The Keurig machine that is used all year around and one wants to use it on Passover needs to be kosherized . The steps to kosherize are noted https://oukosher.org/passover/how-to-kasher-your-kitchen-for-passover/
Unflavored tea bags (including black, white, and green) are acceptable for Pesach without special supervision. Decaffeinated and instant teas require special Passover certification unless listed as approved with a regular OU symbol. See product search or the Passover guide for a complete list.