If you are using a desktop browser, hover your cursor over the link at the top left where it says "Hi, Jennifer!" to see a drop-down menu with a sign-out link.
If you are using the Android version of the eBay app, use the three bar menu icon in the upper left to scroll down to the Settings menu, where you should see a sign out link.
If you are using the iOS version of the eBay app, scroll to the bottom of the page where you should see a My eBay link that leads to a sign-out option.
