Active high-active low for preset
Preset and Clear are two asynchronous inputs in a Flip-Flop.

"Preset" is used to set its output to '1' and "Clear" is used to reset its output to '0'.

Active-low Preset means the Flip-Flop output is set to '1' when the Preset = '0'

Active-low Clear means the Flip-Flop output is reset to '0' when the Clear = '0'

Similarly,

Active-high Preset means the Flip-Flop output is set to '1' when the Preset = '1'

Active-high Clear means the Flip-Flop output is reset to '0' when the Clear = '1'