You have to get your online payslips stamped and signed by your employer.
(You can make a request stating that you want to apply for Bank loan)

You can include a covering letter.
A paper workout of your past earnings (only for those 12 months).
A list of refernces for verification (like HR/Finance)

Hello, I am planning to apply for HSMP in another 2 weeks time. My spouse name is not added in my passport. But I have valid Marriage certificate from Government. Is it any way important to add your spouse name in passport while applying for HSMP? Will it affect their decision in any way? Thanks in ...

Sorry to hear this.
I would suggest you to apply for NARIC without wasting time.
Get your Post graduation verified only if you want to claim points for that.
Otherwise only your graduation is enough.
There is no extra charge for NARIC if you verify your post graduation along with graduation.