Everything I can find out about this little utility, and the site that it's sourced from, suggests that it's perfectly safe to download and install. (I'd be prepared to use it myself, if that's any guide):
https://www.wintools.info/index.php/system-font-size-changer
However, I find the very small text under the icons on my Windows 10 machine perfectly legible anyway. Assuming that you don't need a trip to the opticians, it might be worth a quick check to see if your monitor is properly set up. (Most aren't!). A poorly-configured monitor is often the cause of text becoming less legible. Go here
https://reeddesign.co.uk/testcard.htm
Check that you can easily read all of the numbers, from 0 to 10, across both of the bottom two lines. If you can't, you need to adjust your monitor.