For now, let's add the text. Since there is not much to write, we will do it directly in the frame. But if you're working for a big company, you would consider writing a script that gets the names of each employee and produces the corresponding card.
Let's pick the Insert Text Frame tool in the toolbar (or T shortcut), place the mouse at the top-left corner of the margins, press the left button of the mouse, drag the cursor and draw a rectangle area that will contain the text. Release it when you've reached the bottom-right corner.
Tip
Automatic frame size
If you press the Shift key while clicking in an area, Scribus will automatically create a frame filling this area. An area is defined by the surrounding page borders, guides, and margins. So it should work here. Once the frame is created, double-click on it and you'll see the text insertion beam blinking on top left of the frame.
Type some text, as follows:
