I also use
MyHours. I started using it as I prepared to launch my VA business just so I could get use to it and make it a habit. Thankfully, I did. I signed my first client before I was "officially ready" and had to jump start a project. My first billing went smoothly. I exported the report from MyHours into Excel, edited what I didn't want the client to see (exact time of day worked) and attached as a PDF to my invoice.
Very efficient software which I discovered from this great forum!