// add this line at the top before #import "AppDelegate.h"
#import <React/RCTI18nUtil.h>
//add this line to the didFinishLaunchingWithOptions method before return YES
[[RCTI18nUtil sharedInstance] allowRTL:YES];
[[RCTI18nUtil sharedInstance] forceRTL:YES];
add two below codes to App.js =>
I18nManager.allowRTL(true);
I18nManager.forceRTL(true);