What filename does my PHP initialization file need to use?

The file name your PHP initialization must be as follows:

Note: Managed WordPress accounts also support using php.ini files, but because it's difficult to refresh them when they're updated, we recommend using .user.ini files instead.

More info

• See the PHP documentation for further info on PHP files.
• .user.ini files are only compatible with PHP 5.4 and later, and you can't modify all of the same settings as with php.ini files. For further info, see the PHP documentation for user.ini files.