Hank here from Shopify.
Without sharing your store URL, I will not be able to see what text you are referring to, but I will offer some general assistance here for you. For more specific advice, share your store URL and myself and the community will gladly assist!
Are you referring to the removal of the powered by Shopify text at the bottom of the footer? If so, that guide will talk you through the steps needed to remove this, but I will share the snippet below for you!
If it is to change the name of your store in the footer menu, this can be done in the admin by going to Settings > General and changing your name. Once you click on save, this should change the name of your store in the footer.
Those would be two of the most common questions regarding changing of the text located in your footer, but for further checkout changes, I will share this guide.
Let me know if you have any other questions, or for more specific advice, please share your store URL with the community.
All the best,