Como cambiar el idioma

Thanks for posting here in the Community space, pocas998.

You'll have two options to change the language in QuickBooks Online. Follow the steps below to change it from QuickBooks Online Account and settings.

Here's how:

1. Go to the Gear or Settings icon.
2. Select Account and settings.
3. Click the Advanced.
4. Go to the Language section, then click the small Pencil icon.
5. Hit the dropdown and choose English.
6. Once done, select Save.

Alternatively, you can do it using the language settings of the browser. 

Here's how to change language settings in Google Chrome:

1. At the upper-right of the opened browser, select the vertical ellipsis ⋮.
2. Click Settings.
3. Select Languages.
4. From the Language dropdown, select Add languages.
5. Choose the language you want to use. Then, select Add.
6. Select the vertical ellipsis ⋮ beside the language and then Display Google Chrome in this language checkbox.

For your reference, check out this link for more details: Change language in QuickBooks Online.

I'm also including this link if you want to translate your invoice into another language for future use: Send your invoices in a different language in QuickBooks Online.

If you have further questions, please know I'm only a post or comment away. Have a great day.

This is not true, once you change it to spanish you cannot change it back to english.