Alcohols undergo dehydration (removal of water molecule) in the presence of protic acids (conc. H2SO4,H3PO4 ) at high temperature to give Saytzeff alkene (more alkylated) as major product.
Bulky bases like tert-butoxide, due to steric hindrance, a bulky base abstracts a less hindered proton, that leads to formation of the less substituted product as, the major one, called the Hofmann product.