How do ML model retain/store the learning(s)? In other words, if the model after training and testing is ready for making future predictions, it must be storing the learning(s) somewhere in memory or disk or cache (or I really don't know). 

So, where (how) is it exactly stored?

Hope I asked my doubt clearly for experts to advise.
After generating a predictive model by fitting the data with model.fit(X,y) , "the learnings" are simply coefficients (weights ) that are multiplied by the features ( X ) to give you a certain y. In other words, in the end, what you get is a function that for an input X returns a y, you can store the model on the disk using a joblib or pickle and load it in another environment. machine learning? more like coefficients learning.

Note : This could be edited in case my answer is lacking more details