Short answer
The Companions described his skin as azhar: a bright, radiant colour, neither stark white nor dark brown. Some called him white with a pleasant face. He was an Arab of Quraysh. Islam does not tie virtue to skin colour at all.
The Sunni account, from Anas and others in Bukhari and Muslim, is that the Prophet ﷺ was of a fair, glowing complexion (azhar al-lawn), neither pale white nor dark. Modern race categories did not exist then and do not change anything in faith.
The four schools agree on this.
Explanation
Anas ibn Malik, who served the Prophet ﷺ for ten years, described him as of medium height, with a radiant colour (azhar al-lawn), "not stark white and not dark brown". Abu al-Tufayl said he was white with a pleasant face. Other Companions spoke of a reddish tint in his white skin. Together these describe a light, warm complexion that seemed to shine.
The Arabic words do not match modern race labels. "Abyad" in old Arabic often meant fair or light compared with others in Arabia, and "adam" meant a brown or tan colour. He was an Arab of Quraysh, from the line of Ismail. Trying to fit him into today's categories of "white" or "black" reads modern ideas into old words.
More important is what he taught. Allah says the most honoured of people in His sight are the most righteous, and that nations and tribes exist so people may know one another. Among the Prophet's ﷺ closest Companions were Bilal of Abyssinia, Salman of Persia and Suhayb, called the Roman. He chose Bilal as the first muezzin of Islam.
Muslims do not draw or paint the Prophet ﷺ (see Why can't you draw Prophet Muhammad?). We know his appearance through words. See also What was the Prophet's hair like?
The evidence
Quran, Surah Al-Hujuraat 49:13
يَٰٓأَيُّهَا ٱلنَّاسُ إِنَّا خَلَقْنَٰكُم مِّن ذَكَرٍۢ وَأُنثَىٰ وَجَعَلْنَٰكُمْ شُعُوبًۭا وَقَبَآئِلَ لِتَعَارَفُوٓا۟ ۚ إِنَّ أَكْرَمَكُمْ عِندَ ٱللَّهِ أَتْقَىٰكُمْ ۚ إِنَّ ٱللَّهَ عَلِيمٌ خَبِيرٌۭ ﴿١٣﴾
O mankind, indeed We have created you from male and female and made you peoples and tribes that you may know one another. Indeed, the most noble of you in the sight of Allah is the most righteous of you. Indeed, Allah is Knowing and Acquainted.
Honour in Islam is by righteousness, not colour or lineage.
Sahih al-Bukhari 3547
Sahih... أزهر اللون ليس بأبيض أمهق ولا آدم ...
"Of a radiant colour, not stark white and not dark brown."
Anas's description of his complexion.
Sahih Muslim 2340
Sahih... كان أبيض مليح الوجه ...
"He was white, with a pleasant face."
Abu al-Tufayl's description.
Where the ruling is recorded
- al-Shama'il al-Muhammadiyya (al-Tirmidhi), Chapter on the physical description of the Messenger of Allah. The core reports on his complexion and features.
- Fath al-Bari (Ibn Hajar), Commentary on Kitab al-Manaqib, chapter on the description of the Prophet. Explains azhar, amhaq and adam and reconciles the reports.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.