This topic explains how to target a segment in a flag rule. If you have many flags that need to target the same group of users or other contexts, we recommend that you create a single segment for your flags to target. This lets you manage targeting for that group in one place instead of recreating identical rules in each flag.
To target a segment within a flag rule:

(Optional) Enter a name for the rule.
In the Operator menu, select whether you want contexts in these segments or not in these segments to match the targeting rule.
In the Segments menu, enter or select the segments you want to target.
Segment conditions use OR logic. If you select more than one segment in a “Context is in Segments” condition, the condition matches if the context is a member of any one of the selected segments.
(Optional) Click the + to add additional clauses to your targeting rule.
From the Select… menu, choose a rollout option:
Click Review and save. The “Save changes” dialog appears.
Review your targeting changes, add comments, or request approval as needed.
(Optional) Click Test run to preview the percentage of contexts that will receive each flag variation.
Click Save changes.
Here is an example of a targeting rule for segments:

You can also target a segment starting from the segment itself. Here’s how:
You are taken to the flag’s targeting page to complete the segment targeting rule.