Ramadhan is the muslim holy month of worship where Muslims fast ( not eating , drinking anything) from dawn till dusk. This also includes no sexual activity of any kind as well as no arguments allowed. Its main aim is for the beliver to gain more piety ( god consciousness)

While fasting Muslims are encouraged to recite quran engage in self development, community work, attending masjid for sermons and so much more.

O believers! Fasting is prescribed for you—as it was for those before you1—so perhaps you will become mindful ˹of Allah˺( god consciousness) (2:183)

Through fasting one is able to sympathize with leas fortunate.

Sahih Muslim 1080 a
Ibn Umar (Allah be pleased with both of them) reported Allah’s Messenger (ﷺ) as saying in connection with Ramadan:
Do not fast till you see the new moon, and do not break fast till you see it; but if the weather is cloudy calculate about it.

Sahih Muslim 1080 b
Ibn Umar reported that Allah’s Messenger (ﷺ) made a mention of Ramadan and he with the gesture of his hand said:
The month is thus and thus. (He then withdrew his thumb at the third time). He then said: Fast when you see it, and break your fast when you see it, and if the weather is cloudy calculate it (the months of Sha’ban and Shawwal) as thirty days.

Sahih Muslim 1080 c
This hadith is narrated on the authority of ‘Ubaidullah with the same chain of transmitters, and he said:
If (the sky) is cloudy for you, then calculate thirty days (for the month of Ramadan).

Sahih Muslim 1080 d
‘Ubaidullah narrated on the authority of the same chain of transmitters that the Messenger of Allah (ﷺ) made a mention of Ramadan and said:
The month may consist of twenty-nine days, and it may be thus, thus and thus, and (he further) said: Calculate it, but he did not say thirty.

Quran and hadith on ramadhan

It is made lawful to you, upon the night of the Fast, to be intimate with your wives; they are a garment (protection)for you, and you are a garment for them. Allah knows that you have been betraying yourselves, so He has relented toward you and has been forgoving to you. So now go in to them, and seek whatever Allah has prescribed for you. And eat and drink until the white thread becomes evident to you from the black thread at dawn; thereafter complete (Literally: perfect) the Fast to the night, and do not go in to them while you are consecrating yourselves in the mosques. Such are the bounds of Allah, so do not draw near them. Thus Allah makes His signs evident to mankind, that possibly they would be pious. (1:187)

The Messenger of Allah (ﷺ) said, “Every slave of Allah who observes Saum (fasting) for one day for the sake of Allah, Allah will draw his face farther from Hell-fire to the extent of a distance to be covered in seventy years.”

[Al-Bukhari and Muslim]