There is no standard template to my knowledge.
Probably the most common format used is the biography as a personnel file - as if being called from a database. This lists physical attributes, identifying marks, a personality description or suchlike. Some characters have quotes that indicate their beliefs or allegiances. Others may wish their character to be mysterious or to be defined by their RP interactions and thus have no bio made public. It’s quite varied.
Your best approach may be to look up regular Intergalactic Summit posters’ character profiles in game and read what they write. See what you feel suits you.
My character bio, for example, is of the database style presented as his licence of freedom (as a freed Amarr slave soldier) with some personally meaningful quotes from Scripture.