Iman means faith, the root of a Muslim’s whole way of life. When the angel Jibril (Gabriel) asked the Prophet Muhammad (ﷺ) what faith is, he answered with these six: to believe in God (﷾), His angels, His books, His messengers and the Last Day, and to believe in divine decree, its good and its bad.
The hadith of Jibril,Sahih Muslim 8
AllahGod
That God (﷾) is one, with no partner, no equal and nothing like Him, and that He alone is worshipped.
“Know, therefore, that there is no god but Allah” Qur’an 47:19
Mala'ikahangels
That God (﷾) created angels, who carry out His commands; among them Jibril (Gabriel), who brought the revelation to the prophets.
“Each one (of them) believeth in Allah, His angels, His books, and His messengers.” Qur’an 2:285
Kutubrevealed books
That God (﷾) sent scriptures to His messengers: among them the Tawrat (Torah) to Moses, the Zabur (Psalms) to David, the Injil (the Gospel Jesus preached) to Jesus, and the Qur'an, the last of them, to Muhammad (ﷺ). Muslims believe in these books as God (﷾) first revealed them. The earlier ones were changed over time, so today's Torah and Bible are not those original, uncorrupted revelations. Only the Qur'an is kept exactly as it was revealed.
“Believe in Allah and His Messenger, and the scripture which He hath sent to His Messenger and the scripture which He sent to those before (him).” Qur’an 4:136
Rusulmessengers
That God (﷾) sent prophets and messengers to every people, from Adam and Noah to Abraham, Moses and Jesus, and that Muhammad (ﷺ) is the last of them.
“We make no distinction (they say) between one and another of His messengers.” Qur’an 2:285
Al-Yawm al-Akhirthe Last Day
That this life ends, that every person will be raised and judged for what they did, and that paradise and hell are real.
“Any who denieth Allah, His angels, His Books, His Messengers, and the Day of Judgment, hath gone far, far astray.” Qur’an 4:136
Al-Qadardivine decree
That nothing happens outside God's (﷾) knowledge and will, the good and the bad of it, while people remain responsible for what they choose.
“Verily, all things have We created in proportion and measure.” Qur’an 54:49