Sometimes scientists have created an ORCID iD at some point but have not actively used it. This may be the case, for example, when submitting an article to a journal where the ORCID iD was mandatory and was registered for that reason alone. You should therefore check whether you have already created an ORCID iD. If you do not find anything, for example when you enter your name at ORCID or in your mail archive, then check your earlier publications (especially journal articles) for the indication of an ORCID iD. If an ORCID iD already exists, you can log in with it (if necessary, using the forgotten password function). If there is no indication of an existing ORCID iD, register a new ORCID iD. The data entered will be checked for duplicates, so that you may also come across an existing ORCID iD again.