New cellular data plans on iPad can't be activated with Apple sim. The Apple sim is a card that can be configured with different operator profiles, eliminating the need for a physical sim from the carrier. Macrumors spotted the change.
Apple quietly made the announcement via its cellular data support page, which said that support for new activations using both the standard Apple sim and embedded Apple sim would stop from October 1st, 2022, Anyone who is affected by the change should contact their carrier to find out how to use their data plan on their iPad.
The Apple sim seemed to be a short term solution.
The Apple sim first appeared as a physical card in the iPad Air 2 and iPad mini 3, and went on to be supported by other iPad models, including as an embedded sim in later iPad Pro models. In the US, supported carriers include AT&T, T-MOBILE, and SPRINT. The technical specifications of your iPad can be found on the Apple website. All models of the iPad Pro, iPad Air, iPad mini, and iPad released since October of last year support eSIMs, so there's no need for an apple sim.
The Apple sim seemed to be a temporary measure until Apple could eliminate the world of sim cards completely, as we wrote back in 2014.