L’s n. In the United States, a driver’s license. Editorial Note: In Australia, L’s is widespread and refers to the learner’s “L-plates” and learner’s driving license, precursors to the driver’s permit—one’s P’s—which grants full driving privileges. In the US, the learner’s permit is not issued with special plates. These citations encompass only the American L’s, which refers to the full driver’s license and likely originated independently and more recently. (source: Double-Tongued Dictionary)
Yes “license” is hard to spell.
You realize, I hope, that this probably existed in oral slang before it was ever entered on a keyboard. So ignorance is not the source of this term.