Making “Input Type and Charge Code” view only will involve server file changes, which is not recommended/supported by CA.
However, if you still want this functionality then I will suggest you to look into a file timesheetTemplate.xsl under location $Clarity_Home/META-INF\timeadmin\vxsl\timesheets.
This file contains timesheet object’s properties for the UI, where you can explore the possibility to make these fields view only.