It tends to be 'Fr' or 'Fri'. Both are used.
With a capital F, Friday.
The spelling is Saturday (Saturn's Day).
Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday
Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday.
The correct spelling of the adverb is "probably" (likely).
With a capital F, Friday.
Vendredi is the French word for "Friday".
In Maori, "Friday" is spelled as Rāmere.
Freitag
viernes
The fifth day of the week is Friday.
Pōʻalima [po'ah-lee-ma]
The day name is sexta-feira. ("sixth day")
joyeux Vendredi saint
The spelling is Saturday (Saturn's Day).
Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday
Depending on the part of the world you are in, Friday and Saturday or Saturday and Sunday.