IMI property tax (Council Tax)

Hi everyone.
We bought a property last March so this is our first IMI property tax bill.  My partner and I bought the house together and we have both received a bill for identical amounts but with different document numbers. Do we both have to pay?
Also can the bill be paid by bank transfer as we do not have a cheque book for our Portuguese bank account and are not due back in Portugal until May so cannot use a Multibank to pay.
Any advise would be very much appreciated.

You can use internet banking. Be aware that you should choose the state payment option. The référence has 15 digits to each one of you

Ah, so is IMI a per person tax ( poll tax ) not a per property tax ?

If you have bougth the property 50% possession to each one of you (copropriedade) it's correct

The information has been very useful and thank you for that.
I've visited and registered on portaldasfinancas.gov.pt but can find no link to IMI payments. Am I on the right website?
I can pay at a multi banco next month but will I have to pay a late payment penalty?