Software Heritage is a long-term archive for source code that enables researchers to preserve, reference, and cite software as a first-class research output. The platform captures the code along with its complete development history, thereby contributing to the reproducibility of research results. By archiving repositories (for example from GitHub or GitLab) Software Heritage generates intrinsic, content-based persistent identifiers, so-called "Software Hash Identifiers" (SWHIDs). These allow precise citation of specific versions, files, or even code fragments. The archive integrates with the scholarly ecosystem by supporting standard metadata and citation formats such as codemeta.json or BibLaTeX and promotes proper attribution and reuse of research software.