Free Toad : Download, Install and Run Toad for Oracle (Freeware)

Download link

Toad for Oracle is offered as full feature 30 day Trial version from the download link above.
Register yourself and get going.

You may now launch Toad from windows as below:

Lets connect Free 18c Oracle XE using Toad with following :
User/Schema: SYSTEM
Password: GetStarted18c
TNS Connection
Database: XE
Connect as : SysDBA
Connect Using: OraDB18Home1

Hit Connect. And you’re in !!