The primary way to evaluate officials for UMLC and GNLL games is through ArbiterSports.com. This method is also the only way for MSHSL coaches to get useful feedback to officials. Sign into your Arbiter account and click "Evaluations," then click "Help" on the upper right for further instructions.
The goal of the Arbiter evaluation program is to give officials concrete constructive criticism that can help them to improve. The evaluations are anonymous, and the official can't see any evaluations until at least 5 evaluations have been completed. Specific comments like, "The official missed an offside call because he wasn't on the midfield line when the ball crossed over" are more helpful than things like "The official missed a lot of calls."