Large Font Size in Workbench

This is a common problem with high def monitors as Ansys does not have 4k compatibility. You can right click on Ansys Workbench then open file location. right click again of ansys workbench and go down to properties
 
click on compatibility then go to Change high DPI settings
 
check program DPI, check the override scaling too and change it to System Enhanced. you also better use the DPI to be displayed when you use the program
 
you should then restart your pc. I am sure this should solve the problem, I encountered the same issue with my 4k screen and it is now resolved.
https://forum.ansys.com/discussion/5009/changing-of-font-size