It depends, if you are showing your bank statement as financial proof then its better to attached 3 months salary slip and income tax returns.
but in case if your company is paying u cash then just show the maintained bank statement of 6 months.
Attaching some of your salary slips would be a plus point it will certainly put good impression on the visa officer and make your fule genuine so attach salary slips , offer letter, releiving letter as well. Gud luck for your next steps