In Spanish, as in English, most adverbs are made by adding a suffix to adjectives.
To create an adverb from an adjective that is inflected, i.e ends in -o or -a, inflect the adjective for the feminine form. Then add -mente.
Adjective Adverb rapido rapidamente (quickly) estupido estupidamente (stupidly)
Adjective Adverb verdad verdaderamente (truly) igualdad igualdadamente (equally) ideal idealamente ( ideally)