You could use Custom Events - https://vuejs.org/v2/guide/components.html#Custom-Events
Otherwise, why not include the avatar div and the avatar-form in a wrapper component?
<template>
<div class="avatar-wrapper">
<div class="avatar" @click="showAvatarModal=true">
Show Modal
</div>
<avatar-form v-if="showAvatarModal" :user="user"></avatar-modal>
</div>
</template>
<script>
export default {
props: [
'user'
],
data() {
return {
showAvatarModal: false
}
}
}
</script>