Each time you create a new document and process a search query via the "SEO Workflow", 1 search query credit will be used. This credit is different from the 30 articles/month of the AI Wizard.
For those using the Solo and Basic plans, credits will reset back to a new slate of credits (0 credits used) on the 1st of every month (12 AM UTC time). For Solo and Basic plans, you can see the number of search query credits used. This is not relevant for the Team plan because there are unlimited search query credits.
See how many search query credits you've used for the month in the "Settings" --> "Subscription" page (screenshot below).