Where? When? What? You have not even told us what program, much less anything about the project and its desired use. From simple scaling and letterboxing to more elaborate scan&pan pillarboxing with manual reframing there could be any number of ways, but it will require to actually know the content and some useful details...
Provide the name of the program you are using so a Moderator may move this message to the correct program forum
The Cloud is not a program, it is a delivery process... a program would be Photoshop or Lighroom or Muse or ???