How to change/edit title of sailing child theme
Hi
If you mean website title then go to wp-admin Settings/General Settings and change it from there. If you mean Post/page title then go to edit of that post/page and change it. If you mean widget title then go to Appearance => Widgets and change it.
Otherwise please contact theme Author and let them know How to Contact your purchased theme Author, theme author will be happy to assist you.
Thanks