PBase

I have a photo of my daughter that I would like to change the background. Can anyone tell me what software I can use in order to change the background?

I suggest you Photoshop.
It is not a program that you do it with two clicks. Needs some work but for me it is the best photo editing software.
For help try browsing YouTube cause there are a lot of tutorials
good luck

If the background is a blue screen, it will be easy. Otherwise, be ready to works hours and hours to make a proper selection that won't look strange. Of course if you're only printing 4x6 it's not a problem but for large format, you will have to make a meticulous selection, almost pixel by pixel.

I'm still searching for a solution on a picture of my daughter where she wear whool ... The problem is to select the background without selecting all those fuzzy whool thread. Since the picture was taken with an old and cheap point and shoot camera, there's also lots of chromatic aberations, which doesn't help.

To make a long story short, depending on the picture, photoshop may not always be the magic solution people think it is.

Some backgrounds are easy, here's a before & after example. I used a solid black background as a layer in Photoshop with the photo on top, then 'erased' away the undesirable areas. This one was relatively easy and took about 15 minutes.