In Revit there is fundamentally "two" types of text object. The first is "Annotation Text" and the second is "Model Text".
Annotation text is issued to annotate your views, elements, details, etc. It can be either standalone or "connected" to an object by use of a Leader. The main thing to note about annotation text is that it is "view-specific". It only exists in the view in which it is created.
Model Text is fully 3D and exists within the model and so is visible in all views.
Although it is possible to change Model Text material and thickness (beside text properties like font, justification, size etc), they can not be otherwise edited or ‘exploded’. You can also not accurately 'trace' Model Text as it is not possible to snap to it.
As a model element Model Text must be hosted on a Work Plane. Before Model Text can be placed you need to set the Work Plane accordingly.
Got to a view where you can see where you want to place the Model Text, a 3D view is probably best.
From Home tab, Work Plane panel, select the Set button.....
Then under the "Specify a New Work Plane" heading, select "Pick a Plane".....
Select the plane you want to use:
(you could also draw a reference plane and host it on that)
From Home tab, Model panel, select the Model Text button.....
When you select this tool, you will be presented with an "Edit Text" panel where you can type the text you wish to be created within your Revit model.
Type in you text:
As soon as you click "OK" your model text is created and is ready to be placed on the plane you previously set using the "Work Plane" tool....
Model Text is put on a Subcategory of "Generic Models", so takes on the default object styles of Generic Models. But Model Text does not appear in the families list of the project browser. You can not 'explode' or change Model Text geometry except through it's properties.
Only Model Text Instance and Type parameters can be changed. Select the Model Text, then check out its Properties....
You will notice that you can control it's thickness, what material it is made from and also what Phase it was created / demolished in.
If you need to vary the actual size of the text (ie it's height) or indeed the font it is created from, you will need to edit the "Type" properties and create a new type.....