Hi @abelardo88 ,
prior to version 1.3.0 you have to manually enable the highlighting feature. In the WP admin, go to ‘Search Tools’ and check the setting.
From the 1.3.0 version, the highlight is enabled by default. The background colour is set to black and text colour is set to white. However, both colours can be customized in the ‘Search Tools’ options page in the WP admininstration.