We have learned that it is a Mitzvah on Purim Day to have a Seuda, a meal with meat, with bread, etc. This year, Purim falls out on a Friday. So the question was asked about Seudat Purim when Purim falls out on a Friday. We are all aware of Seudat Shabbat, which is the festive meal we all have on Friday night. So when should we have Seudat Purim so as not to inhibit ones appetite going into Shabbat?
From the Mekubalim, that means the Rashash (Rabbi Shalom Shar'aby Mizrahi), the Kaf HaChayim (Rav Yaakov Chaim Sofer 1870-1939), and others, we learn that it is best to have Seudat Purim in the morning. In fact, they used to have their Seuda in the morning every year, even when Purim fell out on a day other than Friday. And that is in deed the custom of Chacham Ovadia Yoseph, which is to have Seudat Purim in the morning.
Now, when we say the morning, it means at any time in the morning. One should wash, have a meal, and such would constitute fulfilling of the Mitzvah.
If having a meal in the morning is difficult, for timing presents a difficulty, then one should try and have the meal before Chatzot, which is midday. One can be busy delivering Mishloach Manot, giving out Matanot LaEvyonim, etc. So in such a case one should try to have the meal before midday, but if even this is too difficult, then one has until the afternoon to have the meal. The Mishna Berura does bring down that one technically even has until sundown to eat Seudat Purim, and that applies even on a Friday.
So technically, in the worst case scenario, one has until sunset, but preferably one should try and have the Seuda in the morning. If one can not make it in the morning, then try before Chatzot, and if that is difficult, then in the afternoon but as early as possible.
