Ok, so as the title says i want to know if every psu would work on any motherboard you connect it to or is there a compatibility thingy?
If its the second one, will i be able to place any psu on my 042P49 motherboard or it is a bit old for that?
If that is a Dell Optiplex 3010 motherboard, you'll be fine with any modern PSU that physically fits the space in the case.
Dell has stayed with standard connections on their Optiplex line for a long time now. Some pre-builts however have proprietary connections that either require adapters or can't use a retail PSU at all.