If your wallet currency is set to Bitcoin (or a currency different from the currency your bank account is in), a bank deposit will be converted to Bitcoin at the exchange rate as of moment in which the funds arrive in your Abra wallet.
As an example: let's say your Abra wallet is in Bitcoin, and you initiate a US bank deposit today. In 1-2 business days, the funds will arrive in your Abra wallet. At that exact moment, the live exchange rate of US Dollars to Bitcoin will be used to define how much your wallet will receive in Bitcoin.
The same applies if instead of Bitcoin, your wallet is set to a currency different from the currency your bank account is in (for example, your bank account is in US Dollars and your wallet is in Philippine Pesos).