There are two types of volcanoes these are shield volcanoes and strata volcanoes, I will write about the two seperatly.
Shield volcanoes have gentle slopes, which are less than 10 degrees, and have entirly basalt lava flow. They have fissure eruptions which means magma reaches the surface along , linear cracks or fissures. these fissures erupt almost constantly and are not explosive due to the low pressures.
Strato volcanoes form the largest percentage, over 60%, of the earths individual volcanoes. they are very explosive and look like your typical volcanoes with steep sides. The lava that is erupted has high viscosity as it slightly cooler than fissure eruptions. strato volcanoes also contain lots of felsic minerals such as feldspar and contains high amounts of sillica.