I need a AppleCare number

This sounds like your battery is going bad. Check your battery by going to Settings -> Battery -> Battery Health

If your battery health is looking low (like under 75% for instance) then it's time for a new battery or a new iPhone.

Contact Apple for support and service - Apple Support

It’s not clear what your question is. Here are some guesses.

• ”My iPhone isn’t working. It powers off unexpectedly…” Start here. iPhone Repair - Official Apple Support
• ”I need a[n] AppleCare telephone number to obtain service.” Dial 1 (800) APL-CARE (in the U.S.).