When to use it
Use it whenever you describe a team project. Say what you personally did and what changed because of it. Credit the team briefly if you like, but make your own part clear. The interviewer is deciding whether to hire you.
Example
Interviewer: “Tell me about a project you're proud of.”
You: “I led the rollout and cut onboarding time from two weeks to five days.”
In an email or Slack message
Use the same structure on your resume: what you did plus the result. “Led onboarding rollout; cut ramp-up from two weeks to five days.” Use your own real numbers.