The aims set out in the EU treaties are achieved by several types of legal act. Some are binding, others are not. Some apply to all EU countries, others to just a few.
A "regulation" is a binding legislative act. It must be applied in its entirety across the EU. For example, when the EU’s regulation on ending roaming charges while travelling within the EU expired in 2022, the Parliament and the Council adopted a new regulation both to improve the clarity of the previous regulation and make sure a common approach on roaming charges is applied for another ten years.
A "directive" is a legislative act that sets out a goal that EU countries must achieve. However, it is up to the individual countries to devise their own laws on how to reach these goals. One example is the EU single-use plastics directive, which reduces the impact of certain single-use plastics on the environment, for example by reducing or even banning the use of single-use plastics such as plates, straws and cups for beverages.
A "decision" is binding on those to whom it is addressed (e.g. an EU country or an individual company) and is directly applicable. For example, the Council issued a decision on allowing Croatia to adopt the euro on 1 January 2023. The decision related to the country only.
A "recommendation" is not binding. When the Commission issued a recommendation that EU countries’ media service providers improve their ownership transparency and safeguard their editorial independence, this did not have any legal consequences. A recommendation allows the institutions to make their views known and to suggest a line of action without imposing any legal obligation on those to whom it is addressed.
An "opinion" is an instrument that allows the institutions to make a statement in a non-binding fashion, in other words without imposing any legal obligation on those to whom it is addressed. An opinion is not binding. It can be issued by the main EU institutions (Commission, Council, Parliament), the Committee of the Regions and the European Economic and Social Committee. While laws are being made, the committees give opinions from their specific regional or economic and social viewpoint. For example, the European Economic and Social Committee issued an opinion on the Commission’s Next GenerationEU’s small and medium-sized enterprises strategy.