openSUSE by default sets to automatically log in user without having to authenticate with username and password. While convenient, this is a security risk as anyone with physical access to your machine could simply boot it up and access your account.
The option is set up during the installation process but if you've missed that or just simply want to change the setting after the fact, you could still do it via
YaST or the command line.
Steps to disable auto login in openSUSE and SLES using YaST
|openSUSE Leap 15.1|
|openSUSE Leap 15.0|
|SUSE Linux Enterprise Server 15|
|SUSE Linux Enterprise Server 12|
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