When we need to construct a complex object, then Builder Pattern comes into play. Builder Pattern will hide the complexity of the object construction from the user. Builder Pattern will allow the complex object to be built step-by-step.
Using the Factory pattern we generate objects based on some criteria. In Abstract factory pattern, we use multiple factory pattern implementations and generate objects based on that. Abstract factory pattern is also called Factory of Factory, so before reading about Abstract factory pattern, take a look at the Factory pattern.
Singleton pattern is used to ensure that only one instance of a class is created in any case, and whenever you want to get an instance of that class, then the same object instance is returned.