MoA or Memorandum of Association is document that regulates a companies relationships with the external parties. It is a document that specifies companies name, number and name of its members, registered office of company, objects of the company etc. You may also refer to the below mentioned link.
Whereas, AoA or Articles of Association specifies the rules and regulations for the management of internal affairs of the company. It records the rights and duties of the members and the company. ‘Articles of association’ is not the main document of the company. Rather, the most important document of a company is the memorandum of association.It is not compulsory for every company to file articles of association (AoA). Instead of AoA, the company may adopt Table A of the Companies Act.