You can insert them from the insert menu, but you can't import PDF's into container fields using Import Records | Folder--that option is for picture files and text files--PDF's are neither. You may want to scan your documents into an image format such as JPEG instead of PDF.
If you want to import a bunch of documents in a folder into separate records in a batch operation, it can be done but takes some scripting. You might also find acquiring one of the third party plug ins that can list the filenames of the contents of a folder useful in setting up this script.
Thank you for that answer. They have a lot of documents for me to scan and import such as all of the HR, both active employees and former employees. They are basically wanting to electronically organize their company. So I am assuming I will need to do the batch operation. For example Under a Human Resources folder they want sub-folders for Workers Comp. The folder may be empty because that particular person doesn't have a WC claim but in the future if that person does, I would want to scan whatever documents there are pertaining to that and import that into the Worker's comp folder within that employee's name under the HR folder, if that makes sense. I am sure I will need to learn a lot to do this effectively. Is there help for scripting and as far as plug ins go, is there a cost involved?
Plug ins are offered by third party developers. Most must be purchased and prices vary a lot. MooPlug is one that has been offered for free and can list directory contents if I remember correctly.
There are a number of books and training materials on FileMaker and most of them should include information on scripting. We can also help you here as you research how to do this and then get started building and testing your script. One option you'll want to research in FileMaker Help and start familiarizing yourself with is Insert File, which can be done from the insert menu and from a script. WHen used in a script, you can put the filepath to an existing file in a variable and then insert file can use that filepath to insert either a copy of or a reference to a file into a container field. The trick for a batch operation like this is to get a list of filenames from a specified folder--which is where a plug in that can read the contents of a specific directory might be very handy.