I want to invoke some of my custom code during the addition and deletion of TermSets or Term in Term Store Management under Managed Metadata Service. If we can invoke those codes, then how we can implement that?
There are no way to implement an eventhandler on Managed Metadata terms.
(I am presuming that you mean to make adjustments to your Term Store when the managed metadata column is being used).You could have event handlers for custom content types instead (which uses the managed metadata columns). Then, within the event handler make the Taxonomy & Term Store calls. Here are two posts with some details to get you started -