This is a simple process. Depending on your chosen theme, your technical knowledge, and preference settings, the steps might be slightly different, but generally it is the same for all users.

Step 1: Online Store > Themes > Actions > Edit code
Log in to your Shopify store admin. In the admin dashboard, head to the Themes section, find the theme that you want to edit (most likely your current theme).
When you see the Actions drop down tab, click on it and select Edit code
Step 2: Sections > footer.liquid
Open the folder for Sections which will contain the “footer.liquid” file. The coding opens up on the right-hand side.
Step 3: Ctrl + F (Command + F) > Search powered_by_link
Next you will need to open the code search box. If you are using a Mac, press Command and F at the same time. If you are using a PC, press the Ctrl and F. In this example, put “powered by" in the search box to see where it is located in the code.
Step 4: Delete {{ powered_by_link }}
Make sure to delete the following code:
<small class=””site-footer__copyright-content” site-footer__copyright-content–powered-by”=””>{{ powered_by_link }}</small>.
Depending on what theme you are using, there may be more than one instance of this bracketed code that you’ll have to delete. Make sure that any area that includes {{ powered_by_link }} is deleted from the code.
Step 5: Click Save
Once you’ve removed all pieces of code that include "powered by" hit the Save in the upper right-hand corner. Congratulations! You’ve successfully deleted Powered by Shopify from your site.
Notes: Please note that if you decide to change your Shopify theme, you will need to repeat the steps above. Because the changes you make only apply to the theme you have selected.