Click on the logo/name of you company on the menu bar on the top right hand side of the screen.
Click on settings.
Now you can make any changes to the company's information. When you are done press "Update" on the bottom of the page.
If all of the fields were filled in correctly, congratulations you have successfully edited the company's details. If there is something wrong, an error message will appear and it will say if a field was filled out incorrectly and you might need to make a adjustment to it.