* Wonderful is already an adjective. It describes a noun (e.g., "a wonderful day").
* Wonderfully is the most common adverb form, but it can sound a bit formal.
* Wonderously is another option, but it's less common and may sound archaic.
Here are some alternatives, depending on the context:
* Beautifully - if the wonderful thing is visually pleasing
* Magnificently - if the wonderful thing is impressive or grand
* Delightfully - if the wonderful thing is enjoyable or pleasant
* Excellently - if the wonderful thing is done well
* Amazingly - if the wonderful thing is surprising or extraordinary
Example:
Instead of saying "The food was wonderful," you could say:
* "The food was beautifully prepared."
* "The food was deliciously presented."
* "The food was amazingly flavorful."
The best choice depends on the specific meaning you want to convey.