There is an APP called “Sheet Music Bar”, I'll recommend you guys giving it a try.
It has a lot of free sheet music about piano and guitar.
you can find sorts of style like classical,pop,jazz,just searching anything what you want.
Here is app download link: www.77piano.com
I hope it help you to learn more easily.

I am beginner with music, theory, keyboard. Thanks for the information. Good luck!