If we do not want to use those, we can disable using Settings.
We have to Go to
Admin Center --> SharePoint Section
After we get SharePoint manage page,
Then we have to go to SETTINGS section.
To hide DELVE we have to DISABLE "Office Graph" option.
To Hide VIDEO we have to DISABLE "Streaming Video Service" option.
After SAVE and refresh the page. We wont be able to see DELVE icon and VIDEO icon.