For mobile users who need to find words a PDF document, Foxit PDF or Wondershare PDFelement are both good PDF applications for mobile phone devices. Let us take Foxit PDF for iOS for example to figure out how to search for a word in a PDF:
Step 1: Download Foxit PDF from your relevant App Store;
Step 2: Open a PDF document using Foxit PDF;
Step 3: Click the Search button (shown as a magnifying glass icon) and enter the content you need to find in the PDF document, then Foxit PDF will find all the matched items.
However, Foxit PDF only adopts fuzzy search which means it is not a whole-word search. Regardless, it is still a free solution for mobile users to conduct word searches in PDF documents.