To update Magento 2, we go to the Web Configuration Assistant or Web Setup Wizard.
Once we have chosen this, a window will appear for us to choose what we want to do, we will go to the System Upgrade option:
The following window appears, which indicates the most current version of Magento 2, we choose the version we want to update to and click Next.
Now in the window that appears, we click on Start Readiness Check, this will check if the system is ready for the version we want to update to.
Here we see a screenshot after the check, if it doesn't give us any errors, and only some warnings, we can either try to solve it or try to install it.
When we have everything solved, we click Next, in the next window, Magento prompts us to make a current backup of the installation we have, to recover it in case it cannot be updated correctly, we click on Create Backup.
Once the backup is finished, it tells us where it is saved and allows us to continue with the update.
It indicates that the website will be offline while it updates and proposes to put it in maintenance mode while it updates, when we are ready we click on Update.
When we click, a console will appear where it will show us how the update process is going.