The data from both IGS and EPN networks is public and free for use.
However, there exist some strong recommendations on usage and citing of the products.
For usage of IGS products, users must respect the terms of use of IGS products, as indicated in the IGS Data and Product Disclaimer and Terms of Use (5 August 2020). This document is available from: https://www.igs.org/wp-content/uploads/2020/09/IGS-Data-and-Product-Disclaimer-and-Terms-of-Use-200805.pdf.
For usage of EPN products, users must respect the data policy of the EUREF Permanent GNSS Network. This document is available from: https://www.astro.oma.be/common/internet/en/data-policy-en.pdf noting the data were accessed from https://www.epncb.oma.be/_networkdata/data_access/.
In all cases, users must acknowledge previous work and resources as indicated in the “Citation” entry shown on the dataset overview page; this includes citations for the data and access facilities.