The easiest way to share contact information from your iPhone to another iPhone is simply to use the Share Contact feature when viewing a contact to text or email a vCard. A vCard contains all of the contact information you have on file for a contact, and its VCF file format can be read by most modern devices, including Android and Windows phones as well as Macs and PCs.
But what if you want to share contact info with someone who (gasp!) is still holding onto an old flip phone? Or maybe you just want to share a phone number for a contact without any of the other information you have on file for him or her.
In such cases, there is a better way than memorizing a phone number of a contact and then typing it into a text or email message before going back to the contact to double check that you got the number correct. That way is to copy and paste the number.
A contact's page in the Contacts or Phone app may not look like a place where you can copy information, but if you tap and hold on a phone number, a small dialog window will appear to let you copy that number. Then you can head to your text or email app, open up the message you are typing and then tap and hold in the message body for the Paste dialog. No more memorizing and double checking. Just a quick copy and paste.