Europe offers considerable opportunities for existing and young researchers from around the world to study a PhD, a post-doctorate degree and to work as a researcher.

Some points to keep in mind when applying for PhD and postdoctoral studies in Europe

You should have a Master’s or equivalent degree to apply. In some cases, a bachelor’s degree is sufficient.
Make sure you have a unique research proposal or know how your work can contribute to existing research in a field.
Generally, it takes a minimum of 4 years to complete a PhD in Europe, although there are 3- and 5-year programmes available, as well as part-time options.
Fees are typically low or non-existing and good grant possibilities are often offered by host countries, the European Union (EU) and other organisations. You may also be able to gain employment as a researcher during your doctoral studies.
The diversity of opportunities is matched by a system of qualification recognition and credit transfer, meaning that your degree will be internationally recognised and accepted by all countries with an ENIC-NARIC network.

After a PhD, you can pursue postdoctoral work. These positons are somewhat more difficult to obtain and in many cases the researcher will have to provide the funding for his or her research.

 Reference Link:https://ec.europa.eu/education/study-in-europe/news-views/postdoctoral-studies-phds_en