The PIP is delivered in a scheduled conversation, never by surprise and never by email-only. Schedule a 30-minute meeting (in person or video). Both the manager and an HR representative present.
The conversation flow: state directly that you are issuing a PIP, hand over the printed document, walk through each section briefly, answer factual questions (don't debate the assessment in the moment), and confirm the 24-48 hour review window before signature is expected.
What not to do: don't soften the message to the point that the employee leaves unclear about what just happened (this is the most common manager mistake). Don't apologise for issuing it. Don't let the conversation slide into negotiation — the review window exists for that.
In the first 48 hours after delivery: respond to factual disputes in writing, schedule the first weekly 1:1 for the following week, and begin the support commitments immediately. The employee's first impression of whether the plan is serious comes from your behavior in the first week.