Screen shot and steps:

Step 1: Open PUBG Mobile Game and let it load fully to the HomeScreen.

Step 2: On top left screen, below Match Making Options you will find Home icon. Click on it. (Check below image)

Home

Step 3: You will see list of PUBG Custom Rooms along with a search option on top left corner. In the search bar, type the PUBG Custom Room ID that you get from PUBG Player Zone App.

Home

Step 4: Click Enter and if the Room is Protected then you will see a Password Input Pop-up. Just enter the Room Password you get from PUBG Player Zone App and click on Enter Room.

Home

Step 5: That's it. You are in the PUBG Match Custom Room. Change your Position as per your Team or Spot Choice and then wait for the match/game to start.

Home

So this is How you can easily join any PUBG Mobile Custom Room using Room ID & Password. Play Good, Score High Kills and Win Huge!!