The House of Commons Library has produced a list of 7 documents you may wish to bookmark on this.
They include :
European Union citizens who live in the UK are being urged to check their eligibility to vote in the European Parliament elections which take place between the 23rd to 26th of May next year.
UK citizens will no longer be eligible to vote due to the UK decision to leave the EU on the 29th of March 2019. However, citizens of the other EU Countries living in the UK are eligible to vote, subject to certain conditions. A set of country factsheets, produced by the European Parliament, listing voting conditions and national contact points is available here. While some background information on European Parliament elections is here.