Is it obligatory to inform those to whom forbidden emojis were sent that they must be deleted, and is it obligatory to delete insults from a conversation after the person who uttered them repents?

There is no harm in using emojis, and whoever refrains from them out of piety has done well. If a person follows the opinion of those who prohibit them, then it is better for a penitent who has used them to remove their trace if possible, in order to avoid disagreement. This can be done by requesting those to whom he sent them to delete them. His conscience is cleared by this, even if they do not respond. Similarly, whoever insults a person and then repents, must erase what he wrote of the insult if he can do so. This is the most cautious opinion.