Most photographers will tell you that it is important when taking photographs to get it right in camera. This means to take the time to set up your shot, make adjustments to your camera's settings and use things like filters, flash etc. so that you get the best quality image you can that represents what your eye saw at the time. This will result in better image quality and is absolutely true.
Unfortunately, things don't always work out that way. First of all, a photograph rarely captures exactly what you experienced. How many times have you examined your photos and said, "That's not what I remember." Simply put, lenses and cameras do not have the same capabilities of the human eye. Also, we don't always have the time, equipment or skill set to consistently produce awesome images from the get go. You're in a rush, you forgot your tripod or filter, the mosquitoes were driving you crazy.
The fact is, most pro photographers do some editing to their images after they download them from their camera. Although it may be rare, they don't always get it right in camera either. They may only make slight changes such as sharpening or noise removal. Or they may make more drastic adjustments such as white balance and saturation. Let's face it, pro photographers use photo editing software all the time.
Below is an example of a photograph I took that definitely needed some help. This did not represent what I saw, in fact if the scene had looked like this at the time, I never would have pulled over to take the shot. No tripod, on my way home, getting dark, hungry, mosquitoes...... I had all the reasons (excuses) to take a bad photograph.
I would not be denied. Could my photo editing software save this image? Using Lightroom, I made numerous adjustments in an attempt to re-create the actual scene. Contrast, fill light, highlights, gnd filter effect, color saturation and luminance were all manipulated to desired effect. Now notice the new image:
So while it is advantageous to do what we can to get the shot right from the outset, it would be unreasonable to expect that all the time. Making adjustments to photographs after the fact is quite common. In fact, the adjustments made in the photo above are quite minimal compared to what some may do. Nothing was added or cloned out. Check out a magazine cover. Rarely is that the original image. Making a photograph involves making adjustments before, during, and after you take the shot. Everyone will take a different approach. There is no right or wrong. The end result is what really matters.
Did you get it right in camera or after camera? Doesn't matter, just try to get it right.