Hello PraveenReddy6262,
Thank you for posting in the Apple Support Communities. From our understanding, your iPhone XR battery drops 4-5% after 20 minutes, and we'd like to share some information with you that may help.
First, we recommend checking out this article which provides information about iPhone performance in relation to its battery:
iPhone Battery and Performance
Next, we recommend opening Settings > Battery > Last 24 hours, scroll down to the section "Battery Usage by App," then check to see if any apps are consuming significant battery life. Typically, app usage causes the battery to drain. However, you can help maximize battery life. Here’s how:
Maximizing Battery Life and Lifespan
We hope this information is useful. Kind regards.