How Do I Create Effective KPIs for Software Developers and CRM Consultants? Seeking Guidance!

I am tasked with developing KPIs for software developers and CRM consultants in our organization. I have never done this before and have very little knowledge about KPIs. I would appreciate some guidance on what should actually be measured.

Kind regards

I think that the following points can be used as KPIs for software developers:

1) Number of Bugs reported by QA team: The fewer the bugs, the better the performance.
2) Setting deadlines and judging whether the deadlines have been met.
3) Lines of code written: The fewer lines of code written to develop the software, the better the code and performance.
4) Early achievement of deadlines.