1
Press the Windows Key + R to open the Run dialog.
In the resulting box, type cttune.exe and press Enter.
That will open the Clear Type utility, work through that, and on each window, select the clearest and darkest text, to see if that makes the fonts on your screen clearer.
2
With regards to making the fonts bigger, open the Settings app, then go to Accessibility - Text Size.
There is a slider on that settings window to make fonts larger in Windows, that will affect the font size of most of the fonts in Windows user interface.