How do I come about making a picture (eg. a logo) scalable without losing resolution?

Use Adobe Illustrator to make a vectored logo and you can scale that however big you want.

What If it’s something that’s already created in photoshop?

Itll be pixelated depending on how big you want it. When you resize it, it will just stretch the pixels. A vector doesnt use pixels, it just scales everything with a formula.

If you would like someone to take an existing logo and make it a vector, could likely find that here : https://forums.d2jsp.org/forum.php?f=111

Thank you! You were extremely helpful