How to increase the icon text size in Ubuntu 18.04?

How can I increase the icon text size in Ubuntu 18.04? I have tried using gnome-tweaks but I was only able to change font size of window titles and interface items.

Here is a screen shot of three icons from my desktop and I want to change the font size of the text below each icon.

Solution 1:

1. Open dconf Editor. If not yet installed, install it by the following command in terminal.
   sudo apt update && sudo apt-get install dconf-editor -y

2. search with keywords nautilus, open /org/gnome/nautilus/

3. open Desktop and then choose font (Desktop font)
4. give your preferred value.

please see the below pics, where i changed font sizes from 'sans normal' 5,10,15 & 20