See the article What is the difference between iMessage and SMS/MMS? - Apple Support
If you aren’t using iMessage, you can use SMS/MMS. These messages are texts and photos that you send to other cell phones or another iPhone, iPad, or iPod touch. SMS/MMS messages aren't encrypted and appear in green text bubbles on your device.
iMessages are texts, photos, or videos that you send to another iPhone, iPad, iPod touch, or Mac over Wi-Fi or cellular-data networks. These messages are always encrypted and appear in blue text bubbles. To turn iMessage on or off, go to Settings > Messages.
note : you can't send contacts using text messages , contacts will be synced with Mac / iPhone when they are signed in with same Apple ID and password on the same network , in which contacts are added in your Mac address book , the contacts box must be turned as on in iPhone / Mac Set up and use iCloud Contacts - Apple Support
Those contacts will be reflected in www.icloud.com see View contacts on iCloud.com - Apple Support