Do not use gender-specific pronouns (he/she/her/his/hers) unless the person you’re referring to would accept the use of that pronoun.
When writing generically, the use of the singular they is perfectly acceptable and has been for centuries.
Each participant must bring their own laptop.
When the person arrives, thank them for participating.
If for some reason the singular they is not acceptable, prefer the sparing use of he or she. But do not use “punctuational” approaches like he/she or (s)he.
Section 5.265 of the Chicago Manual of Style gives nine techniques for achieving gender neutrality, including helpful examples.