Typically, you can find both of these numbers within the first set of numbers printed on the bottom of your checks, on the left side.
If you don't have a check handy, log into your bank account to find this information. From there you should easily be able to see your accounts and the account number of the account you would like to use.
Note that your bank's ACH Routing Number (also called Routing number, Electronic ABA routing number, ACH routing number, and "Routing/Transit number) is dependent on location. So, be careful if your bank has multiple branches as one bank can have a lot routing numbers for their various locations.