You are able to use the Show If macro to show content to only specific users you choose.
For example, if you are a Lead managing several teams, and you want to share the same page to everyone in your teams, but want to show only specific content to each team, the Show If macro would come in very handy in this situation.
Be aware that content is only hidden in the Confluence page view, and that the content is still available when editing a page, viewing page history, email notifications, etc. In addition, other macros such as Table of Contents (a standard Atlassian macro) can still retrieve the information inside the Show-if/Hide-if macro.
To truly secure sensitive information, consider using the Security & Encryption app instead.
Create a Show If macro on your page.
In the Insert Show If dialog box, decide whether to filter your users using the following parameters: Match Using, Users, or User Groups.
After, choosing which users you want to filter, click Insert.
Within the macro, enter the content you want to share.
When you're done, save the editor.
The page will now only show the content you placed within the Show If macro to the users you specified: