The safest position (usually) for toolchange is the home coordinate, so it's often described as the default toolchange location when writing a new program. I like to use that approach for trying out new programs, or if I don't care about the wasted motion. That's how most CAM systems do it as well, including Fusion.
That said, you can program it to be any coordinate you want, which can be different for each tool if you really want to go that far. For instance if the programmed Z-origin is the right end of your workpiece, giving it Z3.0 might be plenty enough toolchange space for a typical turning tool. But if the next tool is a boring bar or drill, you'll need to add in extra space to account for the next tool's lengthier overhang.