To reach General submenu you have to click on Settings module.
There will be all general informations about your company as address,country, name, VAT number and bank informations.
Also, from here you can change the logo of your company by clicking on the Browse your files and after you find the logo from your computer, just upload it.
If you scroll down, you will see a button calls Other address for invoicing. If you turn it on, another fields will appear below it where you have to add your address for invoicing. If the invoicing address and your company address are the same, just let that option turned off.
On the bottom of you page you have another option that you can turn on/off named Send emails from your on domain name.
Don't forget to Save.