>> Practical Security Assessment (Penetration Testing) - Useful Resources
Some of the samples are presented below:
A list of a lot of pentesting reports
http://isecpartners.github.io/publications/iSEC_Cryptocat_iOS.pdf
Offensive Security Pentesting Report Sample
Pentest Standard Report Sample
InfoSec Institute Report Sample
What you SHOULD NOT do in your report:
Escalate Privileges in Windows 10, 2016 kernel
Windows Privilege Escalation Methods for Pentesters