copy with record with master detail relation ship

I don't know that PHPR gives you a way to do that? So I think you're going to have to code it:

Insert Parent A as new parent B
Get Parent B last identity
Insert Child A into Child B using the last identity as the FK

If you don't know how to do that not sure how you would proceed, except manually.

insert you mean insert it in the database? in phprunner, copy is not yet inserted, it just display via form before inserting it to the database.

I could locally reproduce what you mean, say, the COPY RECORD functionality only works on the fields ABOVE
the items list. If you wish to own a repititive invoicing (e.g. customer gets a weekly or monthly bill of continously
invoiced services), the only chance is to replace the "... on the fly ..." items fields by ordinary 5 or so new entry
fields (assuming 5 items to be the usual maximum of your billing needs). In other words, if 5 permanent items
rows appear as target fields, the COPY RECORD action should work.