It is very important that you make every effort to learn and practice Catalan (its official language). Doing so will make living in Andorra a less stressful experience and will make it easier to meet local people. A higher standard of Catalan will also mean that you will be able to find employment and training possibilities easily.
If you don't speak Catalan, it's advisable to enrol in a course, preferably before landing in Andorra.
If you're planning to work in Andorra, it is also recommended to obtain a formal qualification in Catalan for non-native speakers (Certificats de coneixements de català de la Direcció General de Política Lingüística – Certificate of Catalan level accredited by the Directorate-General for Language Policy (DGPL).
Moreover, once you land in Andorra, you can also enrol a Catalan course in one of its "language academies" as well as other languages offered.
The Ministry of Education also offers courses in Catalan to citizens, over the age of 16, and to companies. They are given in different places of the country in daytime and late-afternoon schedules.
The courses are part of the "Common European Framework of Reference for Languages" and include the six levels comprised at Government of Andorra official examinations, with which the corresponding official Catalan diplomas are obtained.
Courses are face-to-face and the places are limited.
For more information, click on the following link: Cultura.ad (webpage in Catalan only) - https://www.cultura.ad/apren-catala
Finding an exchange partner is the best way to practice a new language with a native speaker. Moreover, language exchange partners can help you understand the culture of the country and inform you of local events to attend. In the best case, an exchange partner will also turn to be your friend.
Many language schools, libraries or even bars, they offer conversation exchanges in Andorra, where you may be able to learn Catalan in exchange for conversing with someone in your own language.
You can find your tandem partner through EasyExpat's forums.