"pagal ho(पागल हो)" means u r mad ("ho" is always used when sentence starts with "tum"(people use it with "aap" also) in present tense )
complete sentence is
(tum) pagal ho (तुम पागल हो )
pagal hai(पागल है)
is sentence about someone who is pagal
wah pagal hai (he/she is mad)
ye pagal hai
ladka pagal hai etc. keep adding nouns(singular) and pronouns(except i मैं and u तुम) sentence is correct
.............. paagal hai
for plural hai है will be changed to hain हैं
-if sentence starts with मैं (main) it always ends with हूँ(hoon) in present tense
eg
correct usage will be
मैं पागल हूँ
[b]main[/b] pagal [b]hoon[/b]
तुम पागल हो
[b]tum[/b] pagal [b]ho[/b]
in two cases above even if u dont say pronouns it is understood that what exactly u mean, or whom u r talking about