how can i save NDVI image .

i am using following matlab command and trying to generate NDVI :

clc

clear

clear all

R= imread('B4.tif');

G= imread ('B3.tif');

B= imread ('B2.tif');

NIR= imread('B7.tif');

NDVI= (NIR -R)./(NIR+ R);

figure, imshow(NDVI);

i am using sentinel-2 satellite image with 10 m spatial resolution, when execute this code , a NDVI is generated. but How can i save image and further process and so that spatial coordinate remain same. When i save NDVI matlab figure window , then it save with .fig extension. but no spatial coordinate embedded.

so kindly the syntax of saving the NDVI image in .tif extension and spatial coordinate also coexsit.

thanks