Generic drugs are copies of brand-name drugs that have exactly the same dosage, intended use, effects, side effects, route of administration, risks, safety, and strength as the original drug. In other words, their pharmacological effects are exactly the same as those of their brand-name counterparts.
"Authorized generic drugs" are generic drugs from branded companies. Aka copycat version of their own brand drug. You will be wondering why do they (brand companies) do that. This way branded companies still make money even though their patent expires.