We use the Estimates (https://docs.oracle.com/en/cloud/saas/netsuite/ns-online-help/section_N1069662.html) feature, and we use the 'Renew' button on the Invoice to create the following year's estimate when a custom renews. Is there a way to do the same but in SuiteScript? I don't see this as an option under record.transform.

Did you try using transform even if it is undocumented? Or maybe use record.copy and trying to set created form manually Other options regarding buttons are actions and macros: docs.oracle.com/en/cloud/…/section_1509640242.html#…

I did, it gives “That type of record transformation is not allowed. Please see the documentation for a list of supported transformation types.”