You may see colour space described only as a quality issue. It is not. It is an adjustment control. Colour space affects the range of colour that can be adjusted in a photo, which you may or may not need. Photoshop or any other editing software gives you two main choices, sRGB and AdobeRGB. Though there are other colour spaces or gamuts as well but these are the ones we are most related to for our practical purposes.
These are first set in your camera (check your manual to see how, though many compact digital cameras offer only sRGB) or from the Camera Raw conversion.
AdobeRGB is the larger colour space and offers more flexibility in controlling colours. However, sRGB (in spite of its reputation as the “monitor colours”) often gives beginning Photoshop users good results faster for printing because change is more limited. With experience, though, most photographers choose AdobeRGB for its control.