My iPhone 13 drops calls often

Hello ArtSal,

Thank you for reaching out to Apple Support Communities.

These step may help with your dropped calls issue:

"Check for a Carrier Settings update

To manually check for and install a carrier settings update:

1. Make sure that your device is connected to a Wi-Fi or cellular network.
2. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.
3. To see the version of carrier settings on your device, tap Settings > General > About and look next to Carrier.

If you insert a new SIM card into your iPhone or iPad, you need to download the carrier settings for your new carrier.

Turn your cellular line off and back on

Go to Settings > Cellular and check to see if your cellular line is turned on. If your cellular line is off, turn it back on. Then check to see if you have service.

If you don't see your cellular line in Settings > Cellular, you should set up an eSIM or insert a physical SIM card. If you're using a physical SIM card, remove the SIM card and put it back in.

If your SIM card is damaged, doesn't fit in the SIM tray, or you transferred your physical SIM card from another device, ask your carrier for a new SIM card. 

Learn more about removing your iPhone SIM card or iPad SIM card.

Reset your Network Settings

Go to Settings > General > Transfer or Reset [Device] > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

Update your iPhone or iPad

Update your iPhone or iPad to the latest version of iOS or iPadOS."

Additional steps can be found here: If you see No Service, Searching, or SOS on your iPhone or iPad

If the issue persists can you provide a few more details? When did you first notice this? Do you experience this in different locations or certain locations? Also, what is your exact iOS version?

Cheers!