You want to tell your friends what time it is. It is 8:45 p.m. how do you say this in spanish
Time is prefaced by Es/Son la/las (time in numbers) and the time clarification for you 12 hr format users.
So if it is 1:15 in the afternoon you would say "Es la uno y quince en la tarde." For plural numbers (everything else) "Son las dos y media en la madrugada." (It is 2:30 in the morning.)
In Argentina and perhaps elsewhere, anything past the half hour is subtracted from the next hour. So to tell your friends that it is 8:45 (in the evening) you would say "Son las nueve menos cuarto" (It is 9 minus a quarter.) Most everywhere else you would just add the minutes: "Son las ocho y cuarenta y cinco en la noche."
It is important to note that the parts of the day are taken very seriously in spanish: mañana is from wake up time to about 11; tarde is the afternoon - 12ish to perhaps 6 pm; noche is when it is dark; and madrugada is when you should be asleep (the early early morning). At least that is what I have encountered in Mexico.