Some countries allow you to choose between WIRE or ACH (sometmes known as iACH for international transfers). ACH takes from 2 to 5 business days, not including weekends (bank do not operate at weekends)
Wire is quicker and easier to track, taking 1-3 business days.
If you want to use ACH then select ACH and link your bank. If you want to use WIRE then link your bank using WIRE. If you want to use both, then link your bank twice, once time selecting WIRE and then again using ACH. Then you can then select either when you transfer.
Caution: please be very diligent entering your bank information. Errors in your account details including you address can cause transfers to be returned to your wallet. The time taken for the return can be up to 3 weeks depending on what country you live in.
Important for US customers. For WIRE transfers, some banks use a different routing number for wire versus ACH. Please make sure you use the correct one.