Is it to correct say in conjunction or with?

It's generally more correct to say "in conjunction with" rather than "with" when you're describing something happening or being used together with something else.

Here's why:

* "In conjunction with" implies a formal collaboration or partnership. It suggests that the two things are working together to achieve a common goal.

* "With" is a more general preposition and can be used in a variety of contexts. While it can sometimes be used to describe things happening together, it doesn't necessarily imply the same level of collaboration as "in conjunction with."

Examples:

* Correct: "We will be offering this service in conjunction with our partner company."

* Less formal: "We will be offering this service with our partner company."

* Correct: "The study was conducted in conjunction with the local university."

* Less formal: "The study was conducted with the local university."

However, there are cases where "with" might be the more appropriate choice depending on the specific context. For example:

* "With" can be used to describe physical proximity or connection. "The table was decorated with flowers."

* "With" can also be used to describe a cause or reason. "He was furious with her."

Ultimately, the best choice depends on the specific context and what you want to convey. However, if you want to emphasize a formal collaboration or partnership, "in conjunction with" is generally the more appropriate choice.