Open application/config/concrete.php. If you don't have a concrete.php file, you will need to create one. Paste the following code into concrete.php if it doesn't exist already. If concrete.php exists and already has arrays of configuration settings, add a comma after the last first level subarray (not the returned array) and then paste the seo part after the comma.
<?php
return [
'seo' => [
'title_format' => '%1$s :: %2$s',
'title_segment_separator' => ' :: ',
]
];
This is a copy of the default configuration settings for formatting the page title. The site name replaces %1$s and any title segments (usually just the page name) replaces %2$s. If there are multiple title segments added with addTitleSegment(), they will be concatenated with the value of title_segment_separator beforehand.
The separator in title_format does not need to match the title_segment_separator even though they are the default values are the same.
Example: changing the title segment separator to a hyphen
return array(
'seo' => array(
'title_format' => '%1$s :: %2$s',
'title_segment_separator' => ' - ',
)
);
Example: changing the title segment separator and the separator in the title format to different values
return array(
'seo' => array(
'title_format' => '[%1$s]: %2$s', // [site_name]: page name
'title_segment_separator' => ' / ', // [site_name]: page name / segment / segment
)
);