At present, there is no official way to move your WhatsApp chat history from Android to the iPhone. There are some unofficial tools, but these are unsupported.
Thankfully WABetaInfo reports that the company is working on an official way to move your chat history.
The team posted the above screenshot, and it seems the only criteria to transfer your chat is that both devices need to be on the latest version of the app.
At present, the release date of this much-in-demand feature it is not known yet, but we are sure it will be accompanied by a big cheer when released.