Welcome to the forum.
I'm going to translate a little bit, if my translation doesn't match reality, please point it out since it will be important.
You have an Appl. TABLE and an Appr. TABLE in the same database on version 8 or later.
Some of the data from Appr. table shows up on layouts based on Appl., but some doesn't when you think it should. This smells like a relationship issue. The quickest way to test your relationship connections is to put both linking fields on the same layout.
Assuming the linking field is "UniqueID", put Applicant::UniqueID and Apprentice::UniqueID next to each other on a layout based on Applicant. Switch the layout to ListView, show all records, and look to see that the fields match. If they don't all match (more to the point, if some are blank), then that's your problem.
Out of curiosity on your Dbase design, why not use a field that holds either "Applicant" or "Apprentice" and just use one file? No relationship would be needed anymore (at least for this limited case, anyway).
Let us know how you progress!