I'll provide some details and steps to resolve this, damaso_lopes.
To remember your credentials in the mobile app, make sure you've checked the Stay Signed In or Remember me box in the Sign-in page.
If the button is selected but you're still asked to sign in, we can do some basic troubleshooting steps. Let's try to refresh your QuickBooks app by following the steps below.
Once done, sign in to QuickBooks on the mobile app and then close it. If you're getting the same result, you'll want to uninstall and reinstall the application to start a clean slate.
To uninstall, here's how:
For downloading the application, you can follow the instructions here: How to download the QuickBooks Online mobile app.
I'm also adding this article for reference: Troubleshooting Quick-Start Guide for the QuickBooks Online app.
Please let me know if you need further assistance with the steps above or other concerns with QuickBooks Online. I'll be right here to help you out again. Thanks.