Where is wordpress search pagination?

I used this 'n my search page:

<?php echo paginate_links(); ?>

It return pagination but I want to add bootstrap pagination to this, But I can't find it, where is this? How can I add class?

Where is wordpress search pagination?

I used this in my search page:

<?php echo paginate_links(); ?>

It returns pagination, but I want to add bootstrap pagination to this, but I can't find it. Where is this and how can I add a class?