ABP CLI and the Get Started page already provides an option to create a new solution with Oracle. See that document to learn how to use. This document provides guidance for who wants to manually switch to Oracle after creating the solution.
This document explains how to switch to the Oracle database provider for the application startup template which comes with SQL Server provider pre-configured.
ABP Framework provides integrations for two different Oracle packages. See one of the following documents based on your provider decision:
Volo.Abp.EntityFrameworkCore.Oraclepackage uses the official & free oracle driver.Volo.Abp.EntityFrameworkCore.Oracle.Devartpackage uses the commercial (paid) driver of Devart company.
You can choose one of the package you want. If you don't know the differences of the packages, please search for it. ABP Framework only provides integrations it doesn't provide support for such 3rd-party libraries.