In a harassment case, identifying yourself makes a big difference. You can report anonymously and it will be handled in the same way (it is your right under Article 7(3) of Law 2/2023), but you should know what happens next, because there are two things that cannot be done without your identity.
The first is protecting you. The organisation’s harassment protocol provides for interim protective measures while the case is being investigated: separating the person concerned, changing shifts or positions, suspending duties. All of them require knowing whom to protect and from whom. If no one has been identified, there is nobody to remove from the risk, and the only possible measure is to take none.
The second is making the report lead somewhere. To sanction an employee, disciplinary proceedings must be conducted in which that person is heard, and if they deny the facts the organisation must be able to prove them. When the only evidence is an anonymous report that nobody confirms and there is no interview with the person who made it, there is usually nothing on which to base a sanction: the case is closed without any warning being issued. Your statement and the subsequent interview are usually the main piece of evidence, and sometimes the only one.
Where sexual or sex-based harassment is concerned, the organisation is required to have a specific procedure for prevention and for handling complaints (Article 12(1) of Organic Law 10/2022 and Article 48(1) of Organic Law 3/2007). That procedure is triggered by specific facts and specific people, and without an identity it cannot move forward.
Identifying yourself does not mean that the person concerned will find out who you are: your identity is not disclosed to them, it is not part of their right of access, and it could only be passed on to the judicial authority, the Public Prosecutor’s Office or the competent administrative authority (Article 33 of Law 2/2023). And if you suffer any retaliation for having reported, the law prohibits it and presumes it to be retaliation.
Whatever you decide, your report is registered and handled. This is information to help you make an informed choice, not a condition.