General interaction:
* Communicate: To exchange information or ideas.
* Engage: To become involved in something.
* Relate: To connect with someone or something.
* Connect: To establish a link or relationship.
* Associate: To join or link together.
More specific interaction:
* Converse: To have a conversation.
* Collaborate: To work together on a project.
* Negotiate: To discuss terms of an agreement.
* Respond: To react to something.
* Influence: To have an effect on something.
* Impact: To have a strong effect on something.
Informal interaction:
* Chat: To talk in a friendly and informal way.
* Hang out: To spend time with someone socially.
* Connect with: To establish a relationship with someone.
The best word to use will depend on the specific context of your sentence.