Customer can tip by percentage or amount desired.

[Jit833]

1) Customer can tip by percentage or amount desired.
2) The are two options on the credit card machine for tip, customer can either tip by entering the amount or by percentage.


*Can I express them in this way? Hope to hear from you soon, thank you.

[Grumpy]

1. Customers can tip either by a percentage of the bill, or by any specific amount desired.
2. There are two options on the credit card machine for tipping. Customers can tip by entering either a specific sum or a percentage of the total bill.

Note that the "Bill" in British English is called the "Check" in American English.

[SoothingDave]

We would understand "bill" in this context. But you ask for "the check" in most places in the US. (In the South, they ask for "the ticket.")

[Gillnetter]

1. Customers can tip either by a percentage of the bill, or by any specific amount desired.
2. There are two options on the credit card machine for tipping. Customers can tip by entering either a specific sum or a percentage of the total bill.

Note that the "Bill" in British English is called the "Check" in American English.

"Bill" could be used in the US, though "check" is more common. If there is a larger amount of money involved I would expect to hear "bill". For example, I ask for a check in a restaurant and a bill in a hotel or from a mechanic.