The most obvious choice for this conversion is to use Adobe InDesign or other professional document preparation software with InDesign format support.
However, most users deal with the problem of how to convert .indd document to PDF format without Adobe InDesign.
Unfortunately, you most likely won't find some simple indd to pdf converter because InDesign formats are not that supported in 3rd party apps. Nevertheless, some users reported to us that you can potentially export .indd files to PDF directly from your Adobe Creative Cloud account that you can create for free. But this option may have been removed in some later versions and is no longer viable.
Mac users also have an option with Art View program, an app that supports viewing (and possibly printing to PDF) of various Creative Cloud documents, including .indd documents from Adobe InDesign.