Quantize 1/4 Note

Set the quantize value to a quarter note. All notes entered will be aligned to quarter note positions on the grid.

Quantize regions in Logic Pro — Apple Support

You can quantize regions in the Tracks area by using the Quantize parameter in the Region inspector. Several advanced quantization parameters are also available in the Region inspector for greater control over quantization.

Logic Pro Quantize parameter values — Apple Support

Important: The Quantize parameter is non-destructive. It adjusts the playback positions of notes in MIDI regions when Logic Pro is in playback or record mode. The original positions are kept in the regions, so you can go back to the original timing.