how to increase the text size here ?

The text size in the menu and side bar are smaller than the operating system text . How do I increase the size of the text circled in blue?

Try resetting the font size in Personalization. Set the slider percentage at whatever you prefer, click ok and wait for Windows to set it. Move it back to the default 100% and have Windows set again. Your font size should be readable again.

If that doesn't work for you set it at the slider percentage you feel lets you read Windows text comfortably.

I don't think you can resize the navigation pane's font but as mentioned above
you can adjust the size of the text for most of the rest of Windows.
You can also resize the font in Notepad by choosing Settings (the gear icon top right in notepad)
and adjust the font to your liking.

Thank you , it looks better

RockyB
This will increase the Text Size on the Whole Page, not just the Left Column.
Not sure if there is a way to just increase the size in that column alone?

Click on Windows Start Button in the Taskbar
Click on the Setting Icon
In the Left Column of Settings click on Accessibility
In the Right Pane, Move the Slider Bar until the Text displayed above is at desired size.
Click on the Apply Button next to the Slider Bar
All Done