The time frame in which Fitrana must be paid is a relatively short period, beginning from sunset on the final day of fasting in the Holy month of Ramadan to just after sunrise on the following day at the beginning of Eid prayers. Payment, however, can be made before this period with companions of the Prophet (Sahabah) having paid Sadaqah-ul-Fitr days before the beginning of Eid. 

Payment was opened up from the middle of Ramadan as word of the Qur’an travelled far and wide to ensure that Fitrana payments would be received by all beneficiaries on the day of Eid. Failure to make this payment before Eid prayers are performed is a sin which cannot be made up for. 

The Holy Prophet SAW has made the charity of Fitr obligatory one saa of barley or one saa of dates for every Muslim, free or slave, male or female. ( Bukhari)

The word Fitrana derived from the Arabic word "فطر " which means to originate, tendencies from birth, or innate nature. When we use it in the context of Ramadan the word "افطار" the evening meal breaks every day’s Fast during Ramadan is best choice. 
Fitrana is a key charity given to the poor at the end of the Ramadan so they manage Eid expenditures, good food and better clothing for the family.

The payment of Fitrana (or Zakat-ul-Fitr) is only permitted to any of the eight groups mentioned in the Surat Al-Tawbah, which are:

• Those less fortunate
• Anyone in need
• Those who are permitted to collect Zakat
• Anyone who has refound Islam
• Slaves or anyone held against their will
• Those who are in debt
• Sadaqah
• Stranded Travellers

Fitrana can only be paid to those listed above and cannot be used for the intention of building new Mosques or schools. 

The Holy Prophet enjoined Fitra charity on Muslims a saa of dates or a saa of barley upon every slave and free man, male and female, young and old, and ordered that it should be paid before the people go out for performing ( Eid-u-Fitar )prayer. ( Bukhari )

Fitrana is compulsory on all Muslims regardless of their status or age. The very poor Muslims those who don’t even have approximately 2kg of essential food are exempted from paying Fitrana.

An old man who was not able to perform fasting in Ramadan due to serious illness or old age is not exempted from paying Fitrana.

The head of the family can also pay Fitrana for his kids, servants and dependents.

The time is limited in this charity Fitrana becomes obligatory from sunset on the last day of Ramadan and remains obligatory until the Eid prayer. It can be paid a couple of days before Eid as many companions of The Holy Prophet used to give Fitrana in Ramadan.

Hazrat ibn Umar would give those people who would accept it and he used to pay it one or two days before the day of Eid-ul-Fitar. ( Bukhari )

The Holy Prophet SAW enjoined Fitra charity on those who fast to shield them from any indecent act or speech, and for the purpose of providing food for needy.whoever pays it before the (Eid) prayer it is an accepted zaka, and whoever pays it after the prayer it is (ordinary) charity of the charities.
( Abu Dawud )

Every Muslim is bound to pay Fitrana at the end of the month of Ramadan as an exchange of gratitude that Allah SWT blessed and enabled him to observe fasting of Ramadan. It’s also a purification for the fasting person from all his bad deeds.

Anas bin Malik narrates from The Holy Prophet SAW, “The fasting of the month of Ramadan will be hanging between earth and heavens and it will not be raised up unless the charity of fitar is paid”.
( kunzul Umaal )