When using historical resources in writing, recording, and publishing (including online) its important to respect the original source.
Utilizing proper citation, even in non-academic works, simultaneously avoids plagiarism and provides the reader with essential information about your source material so they can find it themselves. Due to its unique nature, archival material can present challenges for citation -- particularly because many citation style manuals do not provide adequate guidance on how to cite these materials properly.
When you use archival material, particularly archival material created within the last 100 years, there may be additional rights concerns that you need to be aware of as a researcher, such as copyright, moral rights, Indigenous rights, and privacy rights. An archivist will help you navigate these rights issues, if they apply to your research.