How to produce proof of doing a reading project?

I am a Physics undergrad who wants to be a mathematician. I am thinking of doing a **Reading project** in a pure math topic under an IIT-B prof, for the sake of knowledge itself and also to build my profile. **But how do I produce proof of doing this project**? **This is not a part of an official program**. I was hoping that I could use this for further projects and grad admission opportunities.