If you want to change the text size of element marks then you can do the following:

In Project Manager, right click on the drawing you want and select Properties -> Settings -> Text height.
The default text height is 3.5 times the drawing scale, so if you want to make the text 2 times bigger you type 7.
Next press Ok and Ok and open the drawing.
To get the new text size, go to the tab Plan -> Plan -> Update element mark text size,  now the new text size should appear.
See pictures below:

Figure 1: Project Manager

Figure 2: Update element mark text size