To update content in Umbraco 8, find the content that you want to edit and then find the corresponding component when you log into the website. Here are some steps to do that.
Step 1: Click the dropdown arrow next to Home.
Step 2: Find the page that you want to edit and click the dropdown arrow next to that page.
Step 3: Click the dropdown arrow next to the components folder under the page that you want to edit (this example is the home page).
Step 3: Scroll down to the "content" section of that component and make your changes. Find the text or image that you want to edit and change it.
Step 4: Click Save and publish. OR if you want to preview your changes first, select Save and preview. Then if you're happy with your changes, select Save and publish.