Okay, imagine you have a playground with a lot of different kids playing together. Sometimes these kids might have disagreements or get into fights with each other. This is kind of similar to what is happening in Myanmar, a country far away. Some people there are having problems and aren't treated fairly.
Now, imagine that there is a grown-up who comes to the playground to help out. This is sort of like what the United Nations (UN) does. They are a group of people from all over the world who work together to try to make things better and keep people safe.
So, the UN has sent a special grown-up to help the kids in Myanmar. This grown-up is called a special envoy. They are like a messenger who helps the UN understand what's going on and talks to the people who are having problems. The special envoy tries to find ways to make things better and help everyone get along. They might suggest things like talking things out or finding solutions that work for everyone.
Basically, the United Nations special envoy on Myanmar is someone who is there to help and try to make things better for the people who are having problems in that country. They are kind of like a helper, just like a grown-up who comes to a playground to help kids when they need it.