To sign out from your QuickBooks Online account is so easy, carole-lee-walsh.
You can click on the blue icon beside the Gear icon to sign out from your account. I've attached screenshots so that it's easier for you to follow,
Once you click the blue icon, you'll have the option to sign out.
You can also check out these resources to guide you if you have questions about QuickBooks Online: Getting Started With QuickBooks Online.
Feel free to let me know if you have any questions in QuickBooks. I'll always be here to assist you anytime.