PHP TutorialsPhp What is
PHP INI TutorialsPhp ini What is
Several configuration directives are available for fine-tuning PHP's file-upload capabilities. These directives determine whether PHP's file-upload support is enabled, as well as the maximum allowable uploadable file size, the maximum allowable script memory allocation, and various other important resource benchmarks.
The file_uploads directive determines whether PHP scripts on the server can accept file uploads.
Here have some php ini uploads list.