It is customary for many to store a wet phone in a container of rice in an effort to dry the device before using it. Now, realizing that many people use this method, Apple issued a warning to iPhone users, not to do this.
Apple says rice can enter the cavity of the iPhone, and cause damage to the device. In addition, Apple also said not to use a heater or insert cloth and so on in the cavity in an attempt to dry a wet iPhone.
Instead, Apple advises users to shake or tap the iPhone on the hand with the charging port area facing down (to remove liquid), and then leave the iPhone in a dry place with air flow for at least 30 minutes.
After that, the user can try to charge the iPhone. If there is a warning displayed, then you are advised to leave the phone in a dry place with air flow for about a day before trying to return it.