I sipped my iPhone to apple to get a new battery. there is a no sim on my home screen . how do I proceed?

Apple’s directions:

Before you send your device

Follow these steps before you send your device in for repair or replacement. If it won't turn on or respond, finish as many steps as possible:

1. If you need to send in an iPhone that's paired with an Apple Watch, unpair your devices. When you unpair, your iPhone will create a new backup of your Apple Watch. You can use the backup to restore your Apple Watch when your iPhone returns from service.
2. Back up your iOS device.
3. Go to Settings > Messages and turn off iMessage.
4. Go to Settings > [your name] > Find My [device], then turn off Find My [device] to disable Activation Lock. Enter your Apple ID password, and tap Turn Off.
5. Erase your device. Go to Settings > General > Reset > Erase All Content and Settings. If asked, enter your passcode and Apple ID password. If you can't erase your device because it won't power on or isn't responding, you can erase it from iCloud.com. Learn how.
6. Remove any SIM card, case, or screen protector from your device and keep your cable and charger.

https://support.apple.com/en-us/HT201557#bring

Contact your cellular service provider and get a SIM card.