Start before everyone has signed up
Create the trip, choose the currency you'll settle in and add your friends by name. Share a read-only link in the group chat so everyone can check the balances without an account.
Log it where it happens
Whoever pays adds the expense: who paid, how much, and who it was for. Paid in pounds on a euro trip? Enter the amount in the currency you paid and the exchange rate; balances stay in the trip's currency. Several people chipped in for the villa? Record several payers on one expense.
Restaurant bills, line by line
For the big dinner, use an itemised split: each dish goes to the people who had it, and tax, service and tip are shared in proportion. Snap the printed bill and Hisaab Kitaab reads the lines for you (English, Urdu and Hindi receipts).
A kitty for the shared cash
If everyone puts money into a pot at the start, add a kitty. Pay for things from it, and Hisaab Kitaab tracks what's left and refunds it fairly at the end.
Fewest payments at the end
Hisaab Kitaab works out the smallest number of transfers that settles the whole group. Each person sees who to pay, with a button for PayPal, Venmo, Cash App, Revolut, Monzo, Wise or UPI where the receiver has added it. When the trip is done, close the account and everyone gets a statement by email.