Saving a 3D view in Revit isn't one of the more obvious features if you haven't done it before.
It is however a fairly simple process which I will show you below how to do.
Saving a 3D View
First of you need to be in 3D ideally setup how you want to save it however you can save first and then customise the 3D view.
In the top right corner, Right Click the View Cube.
Then in the menu which appears, left-click Save View.
Revit will then ask you to give the new 3D view a name, once named press OK.
You now have a new saved 3D view, however, you can still change it. To lock the orientation of the 3D view you need to go to your visual tools at the bottom of the view and select the "Unlock 3D View" button and Save the Orientation and Lock View.
Congratulations, you have created and saved a new 3D View.