Balance: Where you can access your GrabPay wallet and view your available balance.
Pay: Where you can access the QR or barcode scanner to pay in-store in partner merchants.
Transfer: Where you can send GrabPay balance to GrabPay wallets of friends & family (NOTE: balance cashed-in using a credit card cannot be transferred to other wallets)
Cash in: Where you can add balance to your GrabPay wallet using a debit/credit card or other in-store and bank options.
Load: Where you can buy mobile load and data packages straight from your Grab app.
Source link: https://www.grab.com/ph/blog/grabpay101/