Hi Pitbul_04,
Thank you for posting in Apple Support Communities. We understand you are concerned about your iPhone becoming warm during use.
"You might notice that your device feels warmer when you:
- Set up your device the first time
- Restore from a backup
- Wirelessly charge your device
- Use graphics-intensive or processor-intensive apps, games, or features, including augmented-reality apps
- Stream high-quality video
These conditions are normal, and your device will return to a regular temperature when the process is complete or when you finish your activity. If your device doesn't display a temperature warning, you can keep using your device."
"iOS and iPadOS devices have built-in protections to prevent overheating. If the interior temperature of the device exceeds the normal operating range, the device will protect its internal components by attempting to regulate its temperature."
"If the device exceeds a certain temperature threshold, it will present a temperature warning screen similar to this:

An iPhone showing this message might still be able to make emergency calls.
To resume use of your device as quickly as possible, turn it off, move it to a cooler environment (away from direct sunlight), and allow it to cool down."
As discussed here: If your iPhone, iPad, or iPod touch gets too hot or too cold
Cheers!