What requirements do I need to enter Malaysia on a social pass? I can stay up to 90 days

My girlfriend moved to Malaysia for work, and I'd like visit her and stay until next year (three months) Do I need a written letter from her inviting me since I'm not gonna be booking hotels? As for funds do I need to meet a certain requirement to cover up the entirety of my 90 days stay? Thanks to everyone in advance and I can't wait to visit Malaysia again, it would be my second time since I visited last year, but this time a little different