It is important to clarify that is a subscription-based professional software. Adobe does not offer a perpetual "free" version of this specific software.
The closest open-source equivalent to Lightroom. It offers non-destructive raw editing and professional color management. Adobe Photoshop Lightroom Classic CC 2018 ​Free...
If you want the "Lightroom experience" without the subscription model, consider these high-quality, free, open-source alternatives: It is important to clarify that is a
Searching for "Free Download" links for Lightroom 2018 on third-party sites is highly discouraged for several reasons: consider these high-quality
You get the powerful editing engine (exposure, color, presets, and cropping) for free.