How do you encourage delegates for training to take part and engage fully? As training is 80% the candidate and 20% the person giving the training,

Ensuring the delegates attend the trainings is very important since knowledge transfer takes the full effect when the message is conveyed to the right mass, completely and correctly.

For this, a clear mention of the importance, objective and target advantages should be seen in the invitations.

As and when they realize the importance of the situation since its sounds serious, they will definitely take part in training. 

The rest depends on how stimulating and engaging the training is.

i would advice them on the important of training and the experience they will get after the the ing the training as one of the tools that help in the employment.

thanks Abukar for your contribution, selling the benefits are key.
I am hoping to get more input to this basic question as participation is everything in the training scenario!!

I agree that encouraging the employees to attend is the biggest challenge when conducting a training.
Few things that i have been doing and might be of help are: - For trainings that might be more of a soft skill that any employee can attend, send out customized invitation that includes the title,location and the outline of the course and have the employees respond if they are interested to attend.
When it is optional you assure attendance because they have taken that decision unlike when it is mandatory.
- For specific course that are addressed to certain group for example sales course, you can ask for the direct managers help to nominate the employees to attend and have their commitments.
- If the training is internal, you can create certificates to give out to attendees - Recognize the employees that accumulate a minimum number of training hours within a quarter/year by giving certificates, small incentive, a notification sent out throughout the company.
I hope these few tips will be of help.