Good friend, from what I understand, the user after logging in would have to the main screen of the App.
Your question needs more technical information for more precise guidance.
Does your app use Storyboard navigation, or is it done programmatically?
The login screen is called by modal, push or is a custom Alertview to be a login screen ?
Assuming that your login screen is another Uiviewcontroller, and requires only a "1 step" to get back to the main one, you can try one of these methods below:
popToRootViewControllerAnimated:
popoverPresentationController
dismissViewControllerAnimated:YES completion:nil
popViewControllerAnimated:
If you are interested in using an Unwind Follow, you can check out this tutorial:
https://spin.atomicobject.com/2014/12/01/program-ios-unwind-segue/
In fact, this is an attempt (valid, I believe) to reply @Diegof, the only problem is that it is bad. Fabio, try to explain your answer better, if there is not enough information in the question, you can comment asking for more information when you have reputation sufficient.
– Jéf Bueno