Check this Add text to a map—ArcGIS Pro | ArcGIS Desktop
But I think they are only available for layouts.
Creating or editing annotations might not be possible as yet.
FAQ: Can annotations be created or edited in ArcGIS Pro?
Thanks Jayanta, Ive dug around a bit looking for this option and came up empty. Hopefully its something esri will implement into Arcpro before we're all forced to switch over from ArcMap to ArcGIS Pro.