Nikon D5500 - Manual (Page 296)

272 B The Setup Menu: Camera Setup
Memory cards must be formatted before first use or after being
formatted in other devices. Format the card as described below.
1
Highlight Yes.
To exit without formatting the
memory card, highlight No and press
J.
2
Press J.
A message will be displayed while the
card is formatted. Do not remove the
memory card or remove or disconnect
the power source until formatting is
complete.
Format Memory Card
G button
➜ B setup menu
D Formatting Memory Cards
Formatting memory cards permanently deletes any data they may
contain.
Be sure to copy any photographs and other data you wish to
keep to a computer before proceeding ( 0 211).