To translate text from English to Portuguese, please go to "Add-ons > Translate > Choose languages" in any open spreadsheet. Select English as source language and Portuguese as target language, then click "Save".
Now you can type English text in one column and see it translated into Portuguese in the next column.
If you have disabled the auto-translate feature, you can select a column range you would like translated and click "Add-ons > Translate > Translate selection".
For details on how to install and use "Translate" add-on, please see this video