In a U.S. district court civil case, how can a party request emails or other documents from another party?

In a U.S. district court civil case, a party may use Federal Rule of Civil Procedure 34 to request designated documents or electronically stored information from another party when the materials are in that party’s possession, custody, or control. [1]

The request must be reasonably specific and fit Rule 26(b)’s discovery limits, including relevance to a claim or defense and proportionality to the needs of the case; the responding party ordinarily gives a written response within 30 days unless the parties agree otherwise or the court sets a different period. [1]

If a party does not produce documents or allow an inspection as requested, Rule 37 permits a motion seeking an order compelling discovery after a good-faith effort to resolve the dispute without court action. This federal overview does not say whether an order would be granted in any case, and it may not govern a state-court case or a request to a nonparty; court-specific rules and orders can also matter. [1] [2] [3]