How do I have to wait my phone if dropped in water.

No. Rice is an old wives tale and can't do anything to stop internal damage to electronics if water got inside.

Water damage cannot be fixed and is not covered by iPhone warranty. You need to schedule an appointment at your Apple Store Genius Bar for evaluation and options. Which will most likely require you to buy what is called an Out of Warranty replacement for about 60% of the cost of the phone when new.

hmm... how long was it under water? Check this article for suggestions:

https://support.apple.com/en-us/HT207043

Should I put my iPhone XR in rice if was dropped in water