Posts from new members (and particularly from new members with Asian-sounding usernames) such as this have a nasty habit of being followed by 'helpful' links from other new members. i.e. they're poorly disguised spam. If such a second post appears, I'll simply don my moderator's hat and ban both members (resulting in the removal of this thread and the link within it).
However, assuming for the moment that this is actually a genuine enquiry, you need to decide what exactly it is that you want to do. If you're simply seeking to add extra functionality to websites (beyond that available via HTML), JavaScript could be very useful to you. However if you're seeking to create Windows programs 'from the ground up', C++ would be better to learn although Python is easier. If, on the other hand, you're hoping to develop Android apps, Kotlin might be best for you.