It's like saying you will put all your effort into something, for example 'she will put all her effort into whatever she does'. So she will try really hard and give it her best to do whatever it is she is doing. I hope I explained that okay and helped you.

It means that she tries as hard as she can. She gives 100% of her energy in order to reach her goal. Example: Sarah will quickly learn English because she gives her all to whatever she does.