i want to use imessage even using cellular data

Hi mariel62,

Welcome to the Apple (user-to-user) Community.

Re: The Messages app

Apple support has an article online that can explain:

What is the difference between iMessage and SMS/MMS? – Apple Support 

With the iMessages app:

Seems if wi-fi (blue messages) is not available for any reason,

then messages are sent over cellular (green messages).

Cellular is also necessary for sending messages to Android phones.

Another article: Set up Messages on iPhone – Apple Support 

says:

"Texts you send and receive using iMessage don’t count against your SMS/MMS allowances in your cellular messaging plan, but cellular data rates may apply." 

So here's all the info. on Cellular Settings:

View or change cellular data settings on iPhone – Apple Support 

If needed:

Messages Support Team Webpage:

There is a "Get Support" link (at the very bottom), of their website (link below)

Messages for iPhone, iPad, Apple Watch, and Mac - Official Apple Support

All the best :-)

Hi

Check that your imessage is toggled ON insettings. Just turn on your cellular data and start sending the imessage.