Regular, unflavored coffee or black tea are considered kosher for Passover without a special certification, but the same is not true for decaffeinated teas and coffees. Rabbi elefant explains the decaffeination process and what makes it problematic for Passover.
For more about Passover with the OU:
What Foods Do Not Require Specific Passover Certification?
Do non-edible items require Passover certification?
Is Baby Formula Kosher for Passover?
Do You Need to Have 4 Cups of Wine at the Seder?