I'm in Mexico and use both Mexican and American banks. My Quickbooks is the Mexican Version. I need to change the base currency to USD as invoices and bills are in USD

It's great to have you here in the Community space, @account-cabodisc.

I've got some steps on how you can change the base currency to USD in your QuickBooks Online (QBO) account.

The currency of an invoice is determined by the currency assigned to your profile. Moreover, you can turn on the multicurrency feature to properly track transactions that include invoices and bills.

Here's how:

1. On the upper right corner, look for the Gear icon.
   
2. Select Account and settings.
   
3. Choose Advanced.
   
4. Click Edit in the Currency section and choose your Home Currency.
   
5. Check the Multicurrency box and confirm you fully understand that you can't undo this option.
   
6. Hit Save, then Done.
   

    

Once you turn on the multicurrency feature, it's important to note that your Home currency is now set and can't be changed anymore. Keep in mind that this feature and foreign currencies are only available in QuickBooks Online Essentials and Plus subscriptions. Therefore, I suggest upgrading your plan for optimal performance if you're using the Simple Start version. 

Furthermore,  I've added these resources you can browse to help you get familiar with using the multi-currency feature in QBO:

• Multi-currency FAQ
• Learn about exchange rates in QuickBooks Online

Please know that I'm here to assist you with any further questions or concerns you may have. Feel free to leave your comments below. Take care and have a great one.