install php7 runtime brackets
// PHP Tooling default configuration settings
"php": {
"enablePhpTooling": true, //false to disable PHP features
"executablePath": "php",//Path format: "C:\\path\\to\\php.exe" for WIN or "/Users/someuser/bin/php" for MAC & Linux
"memoryLimit": "4095M", //Specify a memory limit for the PHP language server process
"validateOnType": "false" //Configuration to have diagnostics "on type" or "on save"
}
//Note: Don't forget to remove comments while using as valid JSONs can't have comments.