PF Payment or treatment for resigned employee case.

One of my employee resigned on 08/12/2017 and last working day will be 08/01/2018. I this case I am paying is Dec+Jan 8 days salary on 08/01/2018. so what about pf payment? should I pay till Jan 8th Pf in Dec return ? or Dec and Jan to different? or only in Jan return itself? please let me know correct process.

december salary paid in jan,
it is not salary for jan 2018

Dec+ jan 8 days total 39 days salary

if last working day is 8th jan 2018, then the return of jan will be filed in feb 2018 with his 8 days contribution

Can't I pay both in Dec return ( Means in Jan 20th return ?

PF is payable after salary is paid, since for Jan 8th you are not going pay to him alongwith salary of Dec'17, the advance PF payment alongwith December contribution (which at any rate would have been paid by now) is not called for and it is better to pay alongwith Jan'18 contribution. However , if you have already paid in advance then seek adjustment by informing local PF office clearly and categorically of the adjustment being done. Otherwise later there would be pointed question when PF authorities inspect you.

no, jan 18 contribution can not be paid with december 17 contrution,
however you can make a single employee challan for 8 days working, after payment of salary subject to the minimum admin charges applicable