Bill is to raise and set sail for French port (6)
I believe the answer is:
calais
'for french port' is the definition.
(Calais is a port in France)
'bill is to raise and set sail' is the wordplay.
'bill' becomes 'ac' (short for account).
'is to raise' is a reversal indicator (in a down clue, letters go up).
'and' is a charade indicator (letters next to each other).
'set' indicates anagramming the letters (instruction to set the letters).
'ac' back-to-front is 'ca'.
'sail' with letters rearranged gives 'lais'.
'ca'+'lais'='CALAIS'
(Other definitions for calais that I've seen before include "French port opposite Dover" , "Northern French port" , "Mary Tudor said it would be found "lying in my heart"" , "end of the tunnel" , "A ferry port in northern France" .)