Save custom sounds in GarageBand for iPhone
You can save, rename, and delete your own custom sounds for each Touch Instrument and use them on another track or in another song. Changes saved include settings for Touch Instruments, master effects, plug-ins, and EQ.
Tap the Track Controls button in the control bar, tap the name of the sound near the top of the track controls, then tap Save.
On iPhone SE, iPhone 8, iPhone 7, or iPhone 6s, tap the Settings button in the control bar, tap Track Controls, tap the name of the sound near the top of the track controls, then tap Save.
Type a name for your custom sound, then tap Done.
The first time you save a custom sound, a new Custom category appears. To rename or delete the sound, tap Edit, then tap the icon (to rename) or the red circle (to delete).
A dot to the left of the name indicates that the settings were modified from the last saved version. Some Touch Instruments also let you save sounds in the same window that opens when you choose a different sound.