Open the ‘Find’ window in any program. This includes your Internet browser/Word Processing programs etc to find text in the current document/web page.
To search online for a certain file type (e.g. PDF) file: Add ‘filetype:’ to your search to display results that only match a certain file type. For example, if you wanted to display PDF results only type:”Manual Name” filetype:pdf — this is a great way to find online manuals.