You can easily adjust the PHP post_max_size according to your website needs using the CloudLinux PHP Selector in cPanel.

1. Log in to your cPanel account.

2. In the Software section, click on Select PHP Version.

3. Click on the Options menu.

Note: If the Options page shows an error related to the native PHP version, switch to a non-native version first.

4. Find post_max_size and click the drop-down menu next to it. Then select the appropriate value according to your requirements.