For a template, see: Do you have a template invitation?
Get clear on what you want the Teylu to focus on, so you can explain this.
Be vulnerable, warm and inclusive.
If the Teylu is in the context of culture change within an organisation, and you hold a leadership position, then it is likely you have been (or are seen as) part of the problem. Acknowledge and apologise for your role in the areas that need addressing. An honest and humble apology shows you are willing to take (and model) personal responsibility and provides a great starting point for building trust.
Say thank you
Make it clear you appreciate and value the people you are inviting and that is why you want them to be part of this Teylu.
Focus on positives, not problems
You may need to mention issues to explain why you feel change is required, but make it clear the Teylu is focused on exploring the future and positive change.
Outline briefly what is involved in being part of a Teylu. It is a personal conversation within a confidential group setting, to build relationships and to explore a particular issue. Share more information on what a Teylu is.
If you do only one thing in your invitation, speak from the heart. By doing this you start as you mean to go on.