I want to donate my old mac to a elderly friend. I have forgotten my password. Is there a way to clean my drives and have the new owner create a new passowrd?

I have MacBook Pro 13 inch with 2.4 GHz Intel Core 2 Duo;

Startup memory: 4GB 1067MHz DDR3;

Graphics: NVIDIA GeFroce 320M 256 MB;

Operating System: macOS Sierra version 10.12.3.

I'd like to give my old machine to an elderly friend but I am unable to remember the password. Will I need to have the password to clean the memory or once the memory is cleaned it will revert to its original factory settings and require my friend to set they're new password?

Thanks

Bill