There is so much that could be stated here, having geographical DNS entries for location is a good option - but I really think you need to read this question. In short I believe there is a master DNS server for a location where the local DNS servers (generally your ISP) update from; not to mention in some situations you can have multiple IP's against a record.
Let's say your DNS is with Digital Ocean; you could have the following:
www.exampledomain.org
138.128.5.69 #Japan
147.158.168.36 #Australia
Employing some third party product (possibly also provided by your website host or DNS provider) when the client asks for the host when looking up a URL it replies with the lowest latency.
I know this is poorly worded, and I will hope that other users will both correct me and improve the answer.
As for obtaining Global Load balancing I will add two examples:
I am in no way affiliated with Incapsula, but you can look at their Global Load Balancing product here or even this product.