Air carrier First Officer reported an incorrect altimeter setting during descent/approach causing the aircraft to be low on approach. Flight crew corrected and landed safely.

Narrative

During the initial descent and approach into ZZZ we unfortunately had dialed in the incorrect altimeter setting. Everything during the flight had been normal throughout unfortunately it was my mistake. We completed a standard descent and approach briefing into ZZZ; we were expecting some moderate turbulence coming in. We were filed to fly the ZZZZZ connected to the RNAV (RNP) XX R. Passing through 18000 ft we started feeling the moderate and our altimeter started flashing at us indicating that it was time for us to input the current altimeter setting. I pressed the knob and it set the last input which was from ZZZ1 (our origination) when I doubled checked the altimeter setting I didn't notice that I had returned to the ZZZ1 tab to check some info and when I pulled the weather in the 'Info & Wx' tab it was feeding me all the weather from ZZZ1. I stated the incorrect altimeter setting as a way to verify and captain verified the same setting with me. We started flying the approach as normal; flight was looking good. We were given clearance to land and also had ATC give us a traffic advisory from a flight that was on approach to XX L. Once that happened we had a TA alert and maintained visual separation. Once we crossed ZZZZZ at 7000 ft and aligned the aircraft with the runway we noticed that our glide path was low. We had 4 red lights on the PAPI. We were configured and not doing any unusual maneuvering. Captain decided to disconnect autopilot leveled off; continued with the approach until we noticed a two-white two red configuration on the PAPI and continued a normal landing with no further incident. Once we debriefed and noticed that we had the incorrect altimeter setting; we decided to write a report due to the chain of errors the might have occurred. We came to the conclusion that there might have been a possible altitude deviation on the arrival as well as approach. Also; from my understanding; while flying the approach; the glide path is not ground based but calculated based on altimeter and GPS. An error in the altimeter setting window might not have the best outcome in the approach phase. The fatigue factor was definitely an issue. Our day started at XA:15 and had 3 legs. Leg one (ZZZ2-ZZZ) started with plenty of issues like weather; maintenance; deicing; deicing equipment failures; flow into ZZZ among others. All these factors definitely compounded into this mistake I made.