How to fix maximum file upload file size error in WordPress

you need to in cPanel and  and wordPress directory and go for pulic_html 
and then search for .htaccess file in your root folder  
make sure all files are visible. if you are not able to find file follow these stpes to solve wordPress upload file issue 
goto wordpress dashboard>Setting>permalinks> scroll down and save without any changes. this will genrate .htaccess file for you.

Right click on .htaccess file and edit it paste this code and save all setting updated :-)

php_value upload_max_filesize 128M
 php_value post_max_size 128M
 php_value memory_limit 256M
 php_value max_execution_time 300
 php_value max_input_time 300

go back and test max file wordPress issue is solved