Problem

1. index.php, line #48:
<?php if ( is_home() && !is_paged() ) { ?><p class="widget-title"><?php _e('Recent Posts','videoblog'); ?></p><?php } ?>

2. style.css, line #760:
#site-content .widget-title, #site-aside .widget-title, .comments-area .comments-title {

but if theme updates in future then these all work will be removed.

Then create a child theme and implement these changes there.
The CSS code can be added via the Customizer and it will stay with a theme update.

sir if I use plugin “Childify Me” as a child theme then it will be fine?

You can try and see.

Thank you I have done it and working fine.
Can you please tell me how can I change yellow color and Black back ground color of Text “Home”
Please check screenshot for more clarification.

https://prntscr.com/e8iuf3

Please use the Google Chrome Element Inspector tool for customization assistance, it will show you the exact CSS rules that correspond to each element.