Hi…,
Welcome.
I presume you are talking FBW FlyPad/MCDU ?
The flightplan input via the MCDU or Flypad is the last OFP created in SimBrief.
You can similarly use that OFP as input to Navigraph Charts. However editing this plan in Charts does not update the SimBrief OFP.
If the edits were significant you could copy from the Type route facility and paste into a SimBrief plan then create OFP again for entry into MCDU or Flypad.
We shall consider such integration for a future release.
Cheers
Ian