After defeating the Ender Dragon a dragon egg should appear in the middle of the bedrock gateway. I only defeated the Ender Dragon in creative but that shouldn't make much of a difference.
Linked issues
is duplicated by 7
MCPE-18356
Dragon egg doesn't appear
Resolved
MCPE-28384
After you kill endardragon there's no egg
Resolved
MCPE-100145
Ender dragon not leaving egg after dying
Resolved
MCPE-117171
End Dragon Egg didn't Appear
Resolved
MCPE-127274
Dragon egg doesn't spawn after defeated Ender dragon second time
Resolved
2 more links
Respawned ender dragons don't make the dragon egg appear. Did you kill a respawned dragon or the original one?