When I was installing the Magento 2, I have got error like $HTTP_RAW_POST_DATA is deprecated from PHP 5.6 onwards and will be removed in PHP 7.0. Then I cant move to next step anymore
You can edit your php.ini to disable always_populate_raw_post_data
1. Open or create your php.ini file,
2. add always_populate_raw_post_data = -1
3 .Save your php.ini
4. Restart php or your web server.