will iPhone 6s come with a sim card?

Hi janefromeast longmeadow,

Thanks for using the Apple Support Communities. Whether or not your new iPhone 6s will come with an included SIM card depends on exactly which configuration you have ordered and where you ordered it from (both store and country). For example, when ordering an iPhone 6s directly from Apple in the US:

When I buy from apple.com, does my iPhone come ready to use?

Yes, if you have selected an iPhone for use on AT&T, Sprint, or Verizon. When your iPhone arrives, all you have to do is turn it on and follow the onscreen instructions to set it up. If you have selected an iPhone for T-Mobile, it will come with the appropriate nano-SIM, but you will need to contact T-Mobile or visit an Apple Store to activate your iPhone. If you have selected an unlocked GSM phone, you can insert your own nano-SIM card or obtain one from the supported GSM carrier of your choice and activate it in order to use your iPhone.

Also, if you plan to use an existing SIM card in a new iPhone, you will want to double check that it is the correct type/format:

Find out which SIM card your iPhone or iPad uses - Apple Support

Cheers