Maximum upload file size is determined by 2 settings in php.ini file. They are upload_max_filesize and post_max_size.
By default, these 2 settings are set as 2MB for upload_max_filesize and 8MB for post_max_size. We can change these values to any bigger ones if you want to allow bigger upload file size.
upload_max_filesize = 40M post_max_size = 41M
To make sure that file uploads work properly, the post_max_size setting should be a little larger than the upload_max_filesize.