RadCallout is like a tooltip with an arrow that can be used to display additional information, warnings, hints, or to highlight relevant data. The appearance of the control can be fully customized to satisfy the needs of your scenarios.
Get familiar with it: https://docs.telerik.com/devtools/winforms/controls/callout/overview
Your question has already been answered in the other thread you have opened on the same topic. Please, see our answer there for more information: https://www.telerik.com/forums/using-callout-as-a-tooltip
We kindly ask you to use just one thread for a specific problem to contact us. Posting the same questions numerous times slows down our response time because we will need to review and address two or more tickets instead of one. Moreover, threads are handled according to license and time of posting, so if it is an urgent problem, we suggest you use a support ticket, which would be handled before a forum thread.
Thank you for your understanding.