Emoji issues


I’m unable to put a emoji next to my twitter name? Please help


I have an iPhone 5 with the latest software upgrade. Everytime I try to save an emoji next to my Twitter name it disappears as soon as I hit save. The only one it will let me keep there is the red heart & I’m tired of it. I’ve done some searches and people keep saying that some emojis just won’t work. I would accept that but I see the same emojis I try to use in other peoples’ Twitter names. Its SO frustrating! Help!