Sometimes I start composing a Gmail on my PC. If I am on the road and make additions editing via smartphone or tablet but Gmail does not automatically synchronize the two drafts.

Is there a simple way to synchronize so I have only truly the same draft on each device?

If you are using a Google, or IMAP, 'client' software then your 'draft' composition should be synchronized back to Google's Gmail/Mail servers so long as your Internet connection is active, then pulled to your other devices when you activate the client software on them.

There is no method to sync two drafts, as each is considered a unique document. You'd have to cut and paste between them manually.

You could instead, compose on Google Drive or Google Docs and access it from all devices, exporting it to Gmail from any of them when it's ready.

Ddave, I admit thinking straight can be at times hard, I go to work on this in 2016

Happy New Year to all of you !!