Finnancial matter.

Hi and welcome to the forum.

- As was mentioned by other members on several other threads (e.g. ATM withdrawal amount), you can use your US card/s to withdraw VND cash here in Vietnam. Some US banks charge a small fee while some others actually refund the transaction fees.

- If you want to carry cash, make sure you declare it at the airport, so later you can deposit your cash into a local VN acct and use their debit card to withdraw cash.

- You can also open a local acct and transfer money from your US acct into the local one.

- If you stick to supermarkets and big shops for all your local purchases, you can use your US  cards at their POS terminals.

Please search for similar discussions on this forum.

All the best!

Thx Senwl. It's very helpful especially for a new comer like me.

To answer your specific questions e.g. how do you pay for food and housing. I think most pay for housing by withdrawing cash via an ATM. If you buy in the bigger chain super markets like Big C or Co-Op you can use your debit card or credit card. You can use both at many restaurants and retail stores as well. For example when I buy appliances, computers, TV's etc I have always been able to use debit card or Credit card. There was a time when most vendors charged a fee to do so. While i always ask if there will be a fee, I have not been charged a fee in several years.

Search the forum for "banking", there are different opinions about whether to have a local bank account, about declaring cash at immigration (law is you have to declare if over USD5000).

From my experience, it is mostly a cash economy.
Leases are paid in cash.
Big supermarkets and appliance/electronic stores take chip credit cards (I never tried a debit card.) More expensive restaurants take credit. Since I rarely buy appliances or go to $10 restaurants, I might use my credit card twice a month at supermarket.
On internet, you can use your credit card just like in your home country, for flights and hotels for instance.
I use ATMs to pull cash from US accounts. No local account.
Cards are fragile and expire and sometimes aren't accepted, so consider backup accounts and backup cards. Nerdwallet.com recommends low fee cards.
Bring backup dollars with you, must be brand new condition bills.