You can change upload limit size in three way
Update php.ini file
There are three settings within the PHP info file that are relevant to your upload limit.
memory_limit = 100M
upload_max_filesize = 100M
post_max_size = 100M
max_execution_time = 300
If you’ve tried the php.ini solutions, and none of them worked.
Trying by editing .htaccess
php_value upload_max_filesize 64M
php_value post_max_size 64M
php_value max_execution_time 300
php_value max_input_time 300
If all else fails, there is one more trick you can try.
3.WordPress Config File
add it in your wp-config.php file