do I need SIM card to use iTunes?

Hello sohaib25,

It sounds as though you're seeing Invalid SIM or No SIM in place of the signal bars on your iPhone. If so, you'll want to complete the steps listed below. These steps can also be found in the following article.

1. "Make sure that you have an active plan with your wireless carrier. 
2. Restart your iPhone or iPad.
3. Check for a carrier settings update. Go to Settings > General > About. If an update is available, you'll see a prompt to select OK or Update.
4. Remove your iPhone SIM card or iPad SIM card from the SIM card tray and then put the SIM card back. Make sure that the SIM tray closes completely and isn’t loose. If you use a SIM tray from a different model iPhone, iPad, or from another phone manufacturer, it might not fit properly.
5. Try using another SIM card. If you don't have one, go to your carrier's retail store and ask them to test with another SIM card. You might need to replace your SIM card."

If you see 'invalid SIM' or 'no SIM' on your iPhone or iPad

If the alert remains after those steps, you'll want to reach out to Apple next. Their contact details can be found via the link below.

Contact - Official Apple Support

If you're seeing an issue where the iPhone shows No Service or Searching, the following article outlines the troubleshooting steps specific to resolving this issue.

If you see No Service or Searching on your iPhone or iPad

Take care!