Is it possible to create a job description inventory on sharepoint?

You can attach files directly to your SharePoint list itself. It's limited to 200MB? If I recall, but for just a few documents you can easily utilize that built in feature for the documents on the list items itself. Wouldn't over complicate it, unless there is a specific reason to link them out to another location.

If you already have them stored somewhere that is accessibly then you could link to the "Single source of Truth" instead of duplicating the files, but you would have to make sure permissions allow the access from the list to the documents that are linked.

Yes, its possible, we are curretnly building a Job descrition library within our organisation in Sharepoint using a document library and a list. The aim is then to use this as a basis for a Power App for Staff / Managers to use to search, add new job descriptions that can then go for approval using Power automate. Also for them to have build in review dates again using power automate and then either have the Jod descriptions updated through an approval process and updated or removed depending on what is needed.