How do I set up a reminder for 3 months after a deal/opportunity is closed?

You can set reminders/tasks using Copper's Workflow Automation. First, navigate to Settings > Automation > Workflow Automation > Add Workflow. Next, make sure you give your automation a sensible name.

Copper's Help Center offers guidance for Workflow Automation recipes for guidance. However, for this use case you can start with a name such as "Follow-up with Customer 3 months after opportunity closure".

Next, configure your trigger:

Opportunity; When a specific field is updated on a Opportunity

Trigger Conditions:

1. Pipeline; Equals; Standard; Sales (if this is from your sales pipeline)

2. Status; Equals; Standard; Won

Filter Conditions:

Select "All of the conditions are met (AND)"

Action 1:

Create; Task

Name; Standard; 3 Month Reach Out

Owner; Use a Formula; assignee_id

Due Date: Use a Formula; DATEADD(CURRENTDATE(),90)

Due Time; Standard; 10:00 AM

Activity Type; Standard; Phone Call

Action 2:

Create; Task

Name; Standard; 6 Month Reach Out

Owner; Use a Formula; assignee_id

Due Date: Use a Formula; DATEADD(CURRENTDATE(),180)

Due Time; Standard; 10:00 AM

Activity Type; Standard; Phone Call