Apex Legends Mobile free to play
EA also answer some commonly asked questions about Apex Legends Mobile on a blog post. Yes, the game will be free to play. However, we can expect to see some cosmetic-only microtransactions such as skins, battle passes and the lines, in the game, similar to its desktop/console version. Cross-play across platforms has been disabled too because Apex Legends Mobile has been specifically designed for touchscreen devices. Support for third-party controllers is unknown at this point, but we should know more about it closer to launch.
As far as gameplay elements are concerned, most of them should remain identical across Apex Legends Mobile and its full version. However, some in-game mechanics will have to be tweaked in the mobile version to make controls less complex. Graphic fidelity could take a hit too, to compensate for the relatively low-power hardware mobile devices run. Some of the early screenshots that EA has posted seem to suggest otherwise, but marketing material is hardly trustworthy.