Direct discrimination occurs when a specific employee is mistreated because of their sex, religion, gender reassignment surgery, etc. Indirect discrimination at work often comes about when there’s a generalised law for all employees, but that might impact one person.
For example, if a company rules that nobody can wear hats or headgear, this could affect a Muslim worker who wears a hijab. A woman could also work in a male-dominated company, be left out of important decisions, or not access a separate toilet.
Indirect sex discrimination happens, but the best way to deal with it is to get support from a specialist.