We should encourage the usage of natural lemmas of Bahasa Indonesia despite "e-mail" has widely known. The "surel" acronym-lemma is registered officially at https://kbbi.kemdikbud.go.id/entri/surel . In fact, there's also "posel" which meaning is similar to both "surel" and "email", but as the "surel" acronym expands as "SURat ELektronik" and "e-mail" basically stands for "electronic mail" and since "mail" is better translated to "surat" in Bahasa Indonesia, I think "surel" is better-fit than "posel" or "e-mail".