Different people use different pronouns that they feel personally expresses their identity the best
For example:
He/him (e.g. someone who may identify as more masculine)
She/her (e.g. someone who may identify as more feminine)
They/them (e.g. someone who may identify as non-binary , genderqueer or gender-non-conforming etc)
Other people may use different pronouns such as ze (etc..)
When meeting someone try to ask for their pronouns, as people may not use the pronouns you 'expect' them to use based on their physical appearance
This can be really helpful for transgender and gender-non-conforming people and make people feel a lot more comfortable :)
(it can also help to prevent people from being misgendered, because you can never assume someones pronouns!)
Trying to ask people their pronouns can also reassure people that they are in LGBTQ+ friendly company and therefore feel safer and more comfortable to express their identity
Doing this can also help to 'usualise' gender variant identities! :)