How to calculate NDWI using Google Earth Engine

Using GEE to calculate NDWI

[@Games_213]

Thanks this was very helpful

[@farahnusrat5639]

Thanks a lot. I am just adding the script of the code for future use. Hope to get more useful tutorials from your channel.
First select your area of interest as ROI and then the script is given below.
var L8 = ee.ImageCollection("LANDSAT/LC08/C01/T1_TOA")
.filterBounds(ROI)
.filterDate("2019-03-09","2020-09-09")
.filterMetadata('CLOUD_COVER', 'less_than', 1)
.mean()
.clip(ROI);
var green = L8.select ('B3');
var nir = L8.select ('B5');
var ndwi = green.subtract(nir).divide(green.add(nir)).rename('NDWI');
var ndwiParams = {min:-1, max:1, palette: ['black','white','blue']};
Map.addLayer(ndwi, ndwiParams, 'NDWI Image');

[@ItsZainabyousaf]

aww so sweet of you. thanks dear

[@qgispro]

Muito bom! Código simples e roda bem.

[@zahraamusaaal-bayati4118]

how can i get the cod

[@justinheiss6060]

Which number is the day and which is the month