For example he throws objects like pencil, toys etc sometimes in
frustration and sometimes he just enjoys. He throws papers outside our
patio and he finds it funny.
Well at my home, my children are allowed to throw, but it requires certain parameters. So when they throw, I acknowledge the reason first. If it is in frustration I would handle that differently than if it's for fun. I will start with handling the "fun" throwing.
I would say
Throwing is very fun! I love throwing things too. That is not for
throwing though. Let's go find something we are supposed to throw.
Then I have things for that. If they want to be outside it might be balls, or even random toys that aren't going to break from being tossed. Indoors, I have a designated area where they can throw soft toys that are in a bin, kept there specifically to be able to throw them.
Now if it's in frustration I might take a different approach.
I see you are frustrated. When I am frustrated sometimes I want to
throw things too. We can't throw things though just because we feel
frustrated. Can you think of things that we can do when frustrated?
How about if we talk about it? Would a hug help you feel better? Can
we try that and see how it feels?
It is not appropriate (in my parenting) to throw things in frustration so I am not prone to taking them over to the throwing bin. If they were to find their way to that bin on their own, fine. I personally don't feel that physical demonstration of such emotions is something I want to encourage since we have to learn how to not act our frustrations out with our bodies. We have to learn to communicate them effectively without such things. There is no classroom or job that will want you throwing things every time you get wound up.
He also screams if he doesn't get his way.
When he screams it would be nice to know what he gets as a response. When my children have screamed in anger/frustration, I tend to make sure I stay totally calm, go quieter if anything, and I reassert that yelling at me is not going to help them change my mind. I tell them I see that they are feeling out of control of their emotions and that maybe we should breathe together and calm down so that they can maybe find words to tell me how they are feeling. I just keep repeating it until they soften and hear it.
I don't and won't punish in such cases. Small kids often have big feelings without any idea how to handle them. It is my job to teach them how to handle those feelings. If I punish them, they are easily likely to misinterpret that to mean they are not permitted to express negative feelings to me. They are not likely to learn better how to cope with them or work through it. To me I see it similarly to them not understanding math and me repeatedly saying "just do it" or making them go to timeout until they can do the math. The fact is, unless we coach and tutor, the idea that they will suddenly grasp the math isn't very likely. Learning how to process your emotions isn't all that different. The hardest part is that many (if not most) of adults I know weren't taught either by their parents. They had to find their way through, often feeling lonely, misunderstood, and not supported by parents through years of emotional development. At the times they were struggling the most with feelings and how to process childhood ups and downs, their own parents left them alone in that struggle. I think that is neither necessary nor the most beneficial approach for the child or the adult.
And I hope anything in there is useful. I just keep the focus of "What do I do here, with this behavior" focused on "How do I help lead my child into the proper thinking and teach them the skills to be able to do this when I am not around". Punishments to me have a huge disadvantage (as do rewards) as they focus entirely on the things you can do when you are present. If they learn how to navigate the choices and make good ones, and learn how to process their feelings like anger, frustration, rejection, disrespect, etc in a true way, they can navigate those things well whether you are around to help them through it or not. They learn how to better balance themselves out, how to problem solve (I WANT to throw this I am so angry. I need to take 10 deep breaths before I do something stupid), etc.
It is what I teach mine. I have 2 grown kids that are now parents and 3 younger ones, down to age 3.