Metro (underground) is one of the most usually ways to move in Barcelona. It is very easy to move in metro in Barcelona, but it is better if you have a map of the metro of Barcelona. Barcelona has a wide underground system that allows you to move wherever you want throughout the city.
Barcelona metro network is operated by TMB company and consists of 8 lines, numbered L1 to L5 and L9 to L11. The lines are distinguished on metro maps by different colors, as you can see in this metro map on the post. FGC lines are numbered L6, L7 and L8. Any of the Barcelona Metro lines have a name of their own but are generally called by their color or by the number and the names of their termini (for example: L3 or Line Green).
The Funicular de Montjuïc, a funicular railway, is fare-integrated and listed on maps as part of the metro network, being connected directly to the metro at Paral·lel station.
There are a lot of metro stations in Barcelona city center (you can see all them in this Barcelona metro map). Some of more famous are Plaça Catalunya, Universitat, Urquinaona, Liceu, Passeig de Gràcia…
In addition, the TMB website has a section that allows you to plan how to get to your destination by metro step by step so you do not miss Barcelona despite having a metro map in your hand 😉