Before starting with iOS development in Unity, familiarize yourself with system requirements and compatibility information.
Unity supports iOS 12 and above. For more information, refer to PlayerSettings.iOS-targetOSVersionString.
iOS devices support Metal. For more information, refer to Metal Graphics API.
Unity supports importing a variety of source format sound files. However, when importing the sound files (except tracker files), they’re always re-encoded to the build target format. By default, these files are in Vorbis format, but you can override them to other formats (such as ADPCM, MP3) for each platform, if required. Vorbis playback provides better compression and quality for iOS compared to MP3 playback.
Unity iOS doesn’t support DXT textures. Instead, iPhone/iPad devices natively supports ASTC, PVRTC, ETC2, and ETC texture compression formats. For more information about iOS texture formats, refer to texture import settings and texture compression format.