Inserting extra vertices / triangles to give the model more geometry I have a lo poly model. 

I would like to give it a bit more geometry here and there. 

This is a screenshot of what I would like to achieve:



The left side shows the "original" object.
On the right side one can see how some extra vertices were inserted. 

This was done in a different software.

How could this be done in Blender?

Thank you very much!

I'm using Blender 2.81.
First, I have to select the faces in question.
To do that, select the face selection.

Select all your faces by using Shift. 

Then, click the "Edge" menu, then click "Subdivide" to subdivide all selected faces.