Environment: SharePoint 2013. I have an inventory list that have a description column and a File Number column. Both columns are 'Single line of text'. When I enter a File number in the 'Find an Item' of the list, it shows results, but when I enter an entry from the description column, it does not show any results. Why is this happening?
The list level search only searches against indexed columns. It requires that the column be indexed. But the multiple lines of text does not support to index as the index column in the list.
If you search it in the site level search box or in the search center, you should get the result.
To resolve that, create a searchable managed property and map the crawled property of this multiple lines of text column to this managed property. Run a full crawl after creating a managed property.
A similar issue: Find an item, search multiline text