Samsung galaxy s5 emoji into mms

[AC Question]

Hi. Help. My emojis on my new s5 are becoming mms. My old iphone still had them as sms. It's not really a problem for me, but my non samsung and iphone buddies. I have unlimited messaging (including mms) some of them don't. I press and hold the microphone button and a emoji icon shows up, I can use them, but only in mms. So I have 2 questions; 1 how do I fix this??? And 2 how will samsung emojis look on iphone? Thank you so much!!