Some viewer to share mindmap

MArginnote is quite a good app. I use it to read some hard texts and i often use the automatic option to add highligted text direc to the map.
After i organise the map to make sense and so i have a quit nice map, often big.
But i find that’s not easy to share it.
It would be fine to have some free viewer that could “view” map (open/close branche) to share this map easily with others. (other people could download just the map viewer).

Sorry for my bad english.