what is the difference between $psprintf and $sformatf while using with `uvm_info macro ?

$sformatf() put the formatted string in verilog reg or string.
$sformatf is an official part of the SystemVerilog LRM and should always be used.

$psprintf is a function that returns the "string". This was an SV extension added by VCS (has origin in Vera) and recently added by Questa as well.
$psprintf is a legacy function that is not part of the SystemVerilog LRM and should never be used.