I know I'm a year too late to answer, but I hope to help the next person reading this thread.
You can create a services ID by following these steps:
Go to https://developer.apple.com/account
Choose "Certificates, Identifiers & Profiles".
Select "Identifiers" on the left-side navigation bar.
Click the + icon next to the "Identifiers" subtitle.
Choose Service IDs and click the continue button.
Fill all of the required fields.
You can also go to this URL https://developer.apple.com/account/resources/identifiers/list/serviceId to see all the services IDs you have been set up.
Edit:
I found the official documentation for adding services ID
https://help.apple.com/developer-account/#/dev1c0e25352
riorafelino
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