Is it permissible to marry a girl with whom one is having an emotional relationship over the phone? And what is the detailed legitimate Islamic way to have sexual relations with one's wife?

Romantic conversations between a man and a woman who are not mahram (definition) are forbidden because they are a means to fall into what displeases Allah, whether they are over the phone or face-to-face. And whoever desires marriage should propose to the girl's guardian or to her if she is mature, and the Shariah permits him to look at her. He must refrain from calls that he labels as a "love relationship."