Footer Settings

Go to Storefront -> My Themes -> Customize. (If your store is a new store, you may need to go to Channel Manager -> Themes -> Edit Theme)

In the Theme Editor -> go to Footer / Footer Settings

When you are happy with your changes, don't forget click Save and Publish to repackage the edited theme.

Power By: Sample Content

// Power By: Text 1
<p class='powered-by'>eCommerce Software by <a href='https://www.bigcommerce.com/theme' rel='nofollow' title='BigCommerce' aria-label='BigCommerce'>BigCommerce.</a></p>

// Power By: Text 2
<p class='powered-by'><a href='https://halothemes.net/' title='BigCommerce Themes by halo.com' aria-label='BigCommerce Themes by halo.com'>Bigcommerce Themes & Templates by Halothemes.net</a></p>

When you are happy with your changes, don't forget click Save and Publish to repackage the edited theme.