Config file not found

[Iam_mine]

I'm trying to use the EstimateKeywordRequest to get traffic volume for keywords.
I'm keep on getting the error below not sure why.

Where is the home directory? Where should I put the adsapi_php.ini ?

PHP Fatal error: Uncaught InvalidArgumentException: Config file not
found as specified: 'adsapi_php.ini' or in the home directory:
'/root/adsapi_php.ini'. in
/home/xxx/adwords/vendor/googleads/googleads-php-
lib/src/Google/AdsApi/Common/ConfigurationLoader.php:63

[Shwetha Vastrad (AdWords API Team)]

Hi,

The PHP client library looks for the configuration file in the home directory of the user running the script. If your home directory is not set correctly or if the library is not able to find the home directory, you can specify the path to the configuration file while creating the OAuth2Credential. If this doesn't work, I suggest that you post your question in the library's repository since this issue is specific to the PHP client library. 

Regards,

Shwetha, AdWords API Team.