Help in french! please!?

No there is not an extra e on elle a mang�. If there is a PRECEDING direct object that is talking about a feminine noun, then there is an extra e. Like if you wanted to say she ate the apple (la pomme), except you wanted to say she ate it you would say "elle l'a mang�e". Or if it is a reflexive verb (se laver) in the pass� compos� (elle s'est lav�e).