Each time you start a new Stata session, Stata looks for two files, sysprofile.do and profile.do. If these finds are found, Stata executes their contents. This post is about how to modity profile.do, in which you can put anything you want Stata to do before you start working with it.
From time to time, I upload my profile.do into my GitHub repository (randrescastaneda/Stata_profile), so you can check it out and download it for your own purposes.