We can see that the default Serif Font is Times New Roman and the default Sans-Serif font is Arial
Font Demo
Impact The quick brown fox jumps over the lazy dog
Arial The quick brown fox jumps over the lazy dog
Times New Roman The quick brown fox jumps over the lazy dog
Castellar The quick brown fox jumps over the lazy dog
Forte The quick brown fox jumps over the lazy dog
Default Serif The quick brown fox jumps over the lazy dog
Default Sans The quick brown fox jumps over the lazy dog