Formality in Lexico-Syntax

[Donald M. Lance]

In an e-mail to someone I know fairly well, I first wrote (a) and then decided to change
'bill' to 'invoice' because that's what will appear at the top of the document in
question.  When I did so, I felt compelled to add the "dative 'to'."  I'm sure I could
omit the 'to' in both (a) and (b) in conversation and could omit it in writing (a) but not
in writing (b).  (I'm doing the paperwork for the annual conference of the Council of
Geographic Names Authorities.)
(a) I'm preparing a bill to send you.
(b) I'm preparing an invoice to send to you.
Comments on your own behavior in the regard?
DMLance