Why does the starting point on the printer bed change?

Can anyone help me figure out why the starting point on the printer bed changes around. My knowledge in 3D printing is Minimal this is the first 3D printer I have owned and I’m below average when it comes to computers. I bought this printer so my son would have something different to do during this lockdown besides play video games and I havent been able to really get it going very well. If there is anyone willing to help it would be much appreciated. Thanks

Do you mean, for the same object? or different ones?
The models are centered by default when you load the STL file, but the starting point depends on the object’s geometry and the setting you use (i.e. Skirt/raft).