1a) Please find attached the working schedule for Helen for December
1b) Please find attached the working schedule for Helen in December
2a) We shall send you the original document by courier after receive your balance payment. Please send us the payment slip ASAP.
2b) We will send you the original document after your remittance. Please send us the payment slip ASAP
Attached is Helen's work schedule for December.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.