'have a discussion' is correct and usable in written English. You can use it when you want to talk about having a conversation with someone. For example: "The teacher suggested that the class have a discussion about the topic".
"We'll have a discussion.
We should have a discussion.
"Let's have a discussion of them".
And we should have a discussion.
If you want, let's have a discussion".
"The four coaches meet together and we have a discussion.
When it's appropriate, I'm sure we'll have a discussion.
Don't make them have a discussion about it".
"If we ever have a discussion, it'll be between us.
"Or let's just have a discussion about it," he says.
Can we just sit down and have a discussion?
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK