Only by opening the form in design view, adding them, and switching back to
form view... which is messy. You're better off creating 'more than you'll
ever need' and then making them invisible according to your record count.
My guess as to what you want to do isn't going to work because you will be
creating unbound checkboxes that are not independent for each record. The
simple thing to do is go to your table and add a field named Selected and
make it Yes/No data type. Each record then will have a bound checkbox and
you will be able to check/uncheck each record independent of all the other
records.