Hi @Peter789136,

if you want to create a dedicated account for REST API you will require to have an available admin license.

For the REST API to work properly a local full admin account must be created, that will be used by the API to make all the calls and have the access to the environment completely.

You can also check more about this in the following documentations: click HERE and HERE.

If you need more help, have further questions, or just want to chat about this topic, please don't hesitate to reach out. 

Thank you!