Correct spelling, explanation: maneuverable is the correct form, in American English*. The origins of the word go to French manoeuvre, meaning manipulation. British English took the word directly from French. In American English, the spelling has been simplified to maneuver. To create an adjective the suffix -able is added, hence maneuverable. Therefore manouverable is a mistaken form.
* Note: In British English the correct form is manoeuvrable.

Definition of maneuverable/manoeuvrable:
adjective, able to be moved, especially carefully, also used in a military context
The valves are convenient as they are easily accessible and maneuverable.
The Armed Forces of Ukraine are forced to conduct maneuverable defense.

Incorrect spelling, explanation: manouverable is an incorrect form both in British and American English. It is a misspelling. The correct form is either maneuverable (in AmE) or manoeuvrable (in BrE). This is because the word has been taken to British English directly from the French manoeuvre and the adjective suffix -able was added. American English spelling has been made simpler (maneuver), therefore the correct form in the US is maneuverable.