Amsterdam has had trams (streetcars) since 1875. The trams are all operated by the GVB (the Amsterdam city public transport company).
To use them, you need an OV-chipcard, like with all other public transport in the Netherlands.
The tram provides a great way to see Amsterdam, and is almost unique to the city (other towns in the Netherlands with trams are Rotterdam, The Hague and Utrecht).
Some important destinations are the Anne Frank House (lines 13 and 17) and Leidseplein/Museum quarter (line 1, 2 and 5).
Tram in front of Amsterdam Central Station