Hi there @DanielHunter. Apologies for my delayed reply! I had to check in with our API Team to get some clarification on the steps you need to take. So here goes:
You would need to create your own Square account and create a Square application. Next, you'd want to use OAuth to ask your Square client for permission to their account. You'll then be able to use your application to make requests on your client's behalf.
Our API Team recommends looking at our OAuth docs to get started.
However to back this all up, if you haven't created an application yet to see your API access token, you can head here to start that process.
Hope this helps!
