Visit the Apps tab of your online Square Dashboard and click Get Started.
Navigate to the Extensions page, and search for Square in the search bar.
Purchase the Square extension and download the file.
Once the file has downloaded, go to: WordPress Admin > Plugins > Add New. Select Choose File.
Upload that zip file you just downloaded (the Square extension).
Next, go to: WooCommerce > Extensions > Settings > Integration > Square.
Select Connect with Square, then log in with your Square username and password. Click Allow on the permissions page that comes up next. This is allowing Square and WooCommerce to connect to each other.
Select That’s my site - redirect me when prompted by the authentication screen.
Once your account is authenticated, fill out the remainder of the fields in the Authentication tab (such as business location and notification email).
Finally, be sure to enable Square as your payment option: go to the Payments tab and click Enable.