Depending on your specific situation, this could be quite involved (or easy), I'm not sure what you mean by "on a different WIFI" but probably it means they are behind a different firewall than you are. If that is the case it might be best to host it somewhere they can access (or take your computer to their network?)
Can you ping the the "others" computer? This doesn't guarantee any other traffic will pass though, but is one test for simple connectivity between computers.
If you can ping their computer, then
- check if you can connect to your neo4j from the host it is running on, if yes docker is probably setup ok
- check if you can get to your neo4j from another computer on your local network, if yes your setup is ok
- then check if the others can connect to it, if no likely you are separated by firewalls that block bi-directional traffic
