Can I go back and add transactions via wells fargo to my account?

Hi there, juliocesar-segur.

It's good to see you in QuickBooks Community!

We can no longer go back to the previous days after you connected your bank. The best thing I can suggest to manually bring in those transactions to QuickBooks Online.

You can log in to your Wells Fargo online banking and download your transactions with either CSV, QFX, QBO, OFX, or TXT file format. Then, you can import the file to your QuickBooks Online account. Please check this article for more detailed steps: Manually upload transactions.

Also, here's the reference on how to categorize and match online bank transactions in QuickBooks Online.

You can post again anytime if you have more questions. Stay safe!