Airtable scripting does not have direct access to other bases.
One option is to use a "transfer table" in base A that is synced to base B. Have the script create the record in Base A. The record will then appear in Base B via sync. If you need further processing in Base B, such as moving data to the actual intended target table, you can use an automation in the Base B. You may also find it useful to add an additional field to the synced table in Base B to track the status of the automation.
Another option is to use the Web API in the script to access the other base. However, the problem with this method is that you have to include your Personal Access Token in the script, which is then visible to everyone with access to the base, which is a security issue.
Yet another option is to use a third party system, like Make. Create a Make scenario that will create the new record in Base B when a webhook is called. Have your script in base A call the webhook with the necessary data. This way your credentials are stored in Make and not exposed to other users of the base.
