Who qualifies for citizenship fee waiver?

Good day, I'm curious about the eligibility criteria for the citizenship fee waiver. Could you please elaborate on who exactly qualifies for this exemption? Are there any specific conditions or requirements that applicants need to meet in order to be considered for the waiver? Additionally, how does the process of applying for the waiver typically work, and what documents or evidence are typically required to support the application? Thank you in advance for your clarification.