You just must have completed Youth Protection training and the Basic Training course for your current Scouting position.  Every role in Scouting except Scoutmasters and Assistant Scoutmasters can now complete their training completely online.

In addition to online training, Scoutmasters and Assistant Scoutmasters should also have completed the Introduction to Outdoor Leader Skills as this is required to be trained for your position.

However, there is no tenure or experience requirement and no special circumstances or invitation required to attend Wood Badge.  Every Scouter in any Scouting role should complete Wood Badge training.  Just complete YPT and Position-Specific training and sign up!