I note that you have a Nikon D7200. It would have come packaged with some fairly useful free software. I don't often use it but Nikon's View NX 2, which came bundled with my D5100, is good for simple adjustments. Nikon also has Capture NX-D, which is similar. Otherwise, you can download GIMP, which is similar to Photoshop but entirely free.
Just use your favourite search engine and you will find the downloads - all free!